Posted By: Adrielp
How good are the P7 engines for drag racing? - 04/08/12 04:39 AM
Pros, cons and such. Thanks!
How good are the P7 engines for drag racing?
Posted By: Oyvind Mopar
Re: How good are the P7 engines for drag racing? - 04/08/12 11:08 PM
Obviously no good at all, seeing your (lack of) response!! 
Posted By: cudaboy
Re: How good are the P7 engines for drag racing? - 04/08/12 11:28 PM
Type P7 into the Google search box at the top of the page. There are a lot of threads about them. Maybe you can find some info there.
Dennis
Dennis
Posted By: Adrielp
Re: How good are the P7 engines for drag racing? - 04/09/12 12:21 AM
Quote:
Type P7 into the Google search box at the top of the page. There are a lot of threads about them. Maybe you can find some info there.
Dennis
I always do my own research but I use the thread to hopefully get to some information a little more easier. In this case its probably a situation where the topic has been brought up before and people don't care to respond again. Unfortunately, I missed that thread lol.
Posted By: fishy340
Re: How good are the P7 engines for drag racing? - 04/09/12 12:29 AM
theres probably 4 guys that have done it,,,that's why there's lack of response 
Posted By: jim sciortino
Re: How good are the P7 engines for drag racing? - 04/09/12 12:32 AM
To get the most out of them, I have no doubt, when ported and assembled for a dragrace application, they are just fine.
Like the SB-2 chevy in a dedicated drag build, they perform excellent.
Like the SB-2 chevy in a dedicated drag build, they perform excellent.
Posted By: S/ST 3040
Re: How good are the P7 engines for drag racing? - 04/09/12 12:41 AM
Bondobob R-5/P-7
Here's Bondo on his one and only shakedown pass.
Recall on the tach showed a 6800 RPM max.
I forget what the car weighed.
Here's Bondo on his one and only shakedown pass.
Recall on the tach showed a 6800 RPM max.
I forget what the car weighed.
Posted By: 340B5
Re: How good are the P7 engines for drag racing? - 04/09/12 12:46 AM
I really like the sound of that thing. Would have thought more rpm.
Some of the parts can be had for a song. So what is the expensive part? (downside)
Some of the parts can be had for a song. So what is the expensive part? (downside)
Posted By: S/ST 3040
Re: How good are the P7 engines for drag racing? - 04/09/12 12:53 AM
Quote:
I really like the sound of that thing. Would have thought more rpm.
Bob was granny-ing it on the new car. (car, suspesion, brakes, engine, rear, etc.)
It dropped a valve headed for the water box the next round.
Just from memory, I think it went 5.83 @ 114 MPH
He would have been shifting it @ 9000+
Posted By: 23T Hemmee
Re: How good are the P7 engines for drag racing? - 04/09/12 04:13 AM
I know of one running in a 1400# Front engine nostalgia dragster running 7.40's at 180+ on injected alky. The dad is a member on here although I don't think he gets on here too much anymore. Basically ran it the way it ran in a round tracker except for changing over to aluminum rods, and slightly different cam profile, buzzing it to 10,000+ fairly regularly. Not really ideal for index racing but drew a lot of attention and other than occasional spring problems was trouble free. Torque, or lack of it would seem to me the biggest problem in a heavier bodied car without a multi-gear tranny (i.e. more than 2-speed). Fair amount of fab work for oil system, bell housings, starters(etc.) but certainly doable for most builders. The P-7 was definitely designed to be a race engine, suprised you don't see more of them in Comp.
Posted By: DemonDust
Re: How good are the P7 engines for drag racing? - 04/09/12 05:35 AM
I'd like to think they preform very well. I've had a best of 109 mph 6.934 in the 1/8 on glare ice. And that was with a brand new setup. Still working on it.. Getting rid of the leaf springs and putting ladder bars in.
I'm hoping to get it to the asphalt a few times this summer and see how it does.
R5P7 in a duster 1/8 mile ice drag strip
I'm hoping to get it to the asphalt a few times this summer and see how it does.
R5P7 in a duster 1/8 mile ice drag strip
Posted By: LA360
Re: How good are the P7 engines for drag racing? - 04/09/12 07:07 AM
For an all out drag racing application you would start with a set of raw castings that you would send to someone like CFE or Slawko (I know these two companies have done development on these heads)
They are a very good, well engineered engine that can perform well. I do think that a oval track head with a drag racing specific camshaft could also run a decent number also. You won't be running anything under 6500-7000 in stall speed, in an all out application is it going to be closer to 8500-9000.
An all out engine is going to cost plenty of $$$, you're not going to get any change out of $60-80K
They are a very good, well engineered engine that can perform well. I do think that a oval track head with a drag racing specific camshaft could also run a decent number also. You won't be running anything under 6500-7000 in stall speed, in an all out application is it going to be closer to 8500-9000.
An all out engine is going to cost plenty of $$$, you're not going to get any change out of $60-80K
Posted By: Georg
Re: How good are the P7 engines for drag racing? - 04/09/12 07:50 AM
Going to swap my Charger with Valiant soon and prepare to install my R5/P7 into it.
Ofcorse this Valiant dont have best tranny for R5 motor ( PowerGlide with 6500 RPM torque converter ) but car is pretty light....so we will see later this summer hopefully how it works out
Ofcorse this Valiant dont have best tranny for R5 motor ( PowerGlide with 6500 RPM torque converter ) but car is pretty light....so we will see later this summer hopefully how it works out
Posted By: 23T Hemmee
Re: How good are the P7 engines for drag racing? - 04/09/12 03:00 PM
Quote:Maybe that much in Oz with all of the shipping charges you guys have to endure, but my friend in the dragster has less than $20K in his and almost $6K was in the Engler Fuel Injection, and dry sump system. I forgot to mention, they don't have have any provision for wet-sump oiling, so dry-sump is a necessity.
An all out engine is going to cost plenty of $$$, you're not going to get any change out of $60-80K
Posted By: B3422W5
Re: How good are the P7 engines for drag racing? - 04/09/12 03:53 PM
The best( and about only) example of a P7 motor drag racing on this forum was my buddies 68 Dart he raced all summer, year before last.
68 Dart 3000 pounds with driver
904
Old busch restrictor plate motor. Small 248/258 roller cam, compression was at about 12 to 1.
He used old w2 2 inch headers he made work
4150 carb, forget how big.
Car went low 9.40's at 142-143 MPH, probably put 50-60 passes on it, then sold the motor to one guy, and the car to another.
So with probably not the " best" p7 motor to use, he still got it to fly.
With bigger cam and more compression i have no doubt it could have threatened the 8's. Those heads are just darn good.
68 Dart 3000 pounds with driver
904
Old busch restrictor plate motor. Small 248/258 roller cam, compression was at about 12 to 1.
He used old w2 2 inch headers he made work
4150 carb, forget how big.
Car went low 9.40's at 142-143 MPH, probably put 50-60 passes on it, then sold the motor to one guy, and the car to another.
So with probably not the " best" p7 motor to use, he still got it to fly.
With bigger cam and more compression i have no doubt it could have threatened the 8's. Those heads are just darn good.
Posted By: DemonDust
Re: How good are the P7 engines for drag racing? - 04/09/12 04:13 PM
Quote:
The best( and about only) example of a P7 motor drag racing on this forum was my buddies 68 Dart he raced all summer, year before last.
Wow, a little arrogant there.. Just cause I don't race asphalt, I'm not good enough to be an example??? I'm glad your BUDDY is the only one GOOD enough to be taken into consideration in this forum... Just another example of all you clicky azzholes on here... IF you don't drag race assphalt you're no good...
Posted By: B3422W5
Re: How good are the P7 engines for drag racing? - 04/09/12 04:18 PM
Quote:Quote:
The best( and about only) example of a P7 motor drag racing on this forum was my buddies 68 Dart he raced all summer, year before last.
Wow, a little arrogant there.. Just cause I don't race asphalt, I'm not good enough to be an example??? I'm glad your BUDDY is the only one GOOD enough to be taken into consideration in this forum... Just another example of all you clicky azzholes on here... IF you don't drag race assphalt you're no good...
Last i checked this is a drag racing forum. I wasnt trying to be arrogant, just stating a fact, he actually raced one a whole season. Only person i know who has done so.
Lighten up dude, i didnt say he was good, bad or indifferent, just said he raced it, and posted his basic combo and what it ran.
Your ice racing deal has zero to do with this forum, unless they changed it from drag racing.
I have posted on here for 10 years, go pack sand.
Posted By: produster
Re: How good are the P7 engines for drag racing? - 04/09/12 04:30 PM
The one down fall I have heard on these motors is the valve stem size and running a bigger spring pressure for bigger cam for drag racing. But I know they, valve guides can be made bigger.
I think that is the biggest down fall of these motors for drag racing. A cam change, better intake, bigger carb, a little off the head to up the compression and you can look in upwards of 1000hp. If given the time and effort you could have a killer set up.
Only issue is the limited amount of trans stuff. Jesse is the only one I know doing some sort of adapter.
When my project is a little more firm I will reveal what I am doing and let the nay sayers tear it apart.
I think that is the biggest down fall of these motors for drag racing. A cam change, better intake, bigger carb, a little off the head to up the compression and you can look in upwards of 1000hp. If given the time and effort you could have a killer set up.
Only issue is the limited amount of trans stuff. Jesse is the only one I know doing some sort of adapter.
When my project is a little more firm I will reveal what I am doing and let the nay sayers tear it apart.
Posted By: DemonDust
Re: How good are the P7 engines for drag racing? - 04/09/12 04:31 PM
Quote:Quote:Quote:
The best( and about only) example of a P7 motor drag racing on this forum was my buddies 68 Dart he raced all summer, year before last.
Wow, a little arrogant there.. Just cause I don't race asphalt, I'm not good enough to be an example??? I'm glad your BUDDY is the only one GOOD enough to be taken into consideration in this forum... Just another example of all you clicky azzholes on here... IF you don't drag race assphalt you're no good...
Last i checked this is a drag racing forum. I wasnt trying to be arrogant, just stating a fact, he actually raced one a whole season. Only person i know who has done so.
Lighten up dude, i didnt say he was good, bad or indifferent, just said he raced it, and posted his basic combo and what it ran.
Your ice racing deal has zero to do with this forum, unless they changed it from drag racing.
I have posted on here for 10 years, go pack sand.
Are you kidding me?? I know it's a drag racing forum you frickin Douche. How is drag racing on ice not drag racing??? Please tell me sir why I don't qualify? Sorry my 7 years isn't good enough for your 10.. Once again you go with I'm bigger and better then you...
And I have 3 seasons drag racing on mine...
Posted By: B3422W5
Re: How good are the P7 engines for drag racing? - 04/09/12 04:32 PM
Quote:
The one down fall I have heard on these motors is the valve stem size and running a bigger spring pressure for bigger cam for drag racing. But I know they, valve guides can be made bigger.
I think that is the biggest down fall of these motors for drag racing. A cam change, better intake, bigger carb, a little off the head to up the compression and you can look in upwards of 1000hp. If given the time and effort you could have a killer set up.
Only issue is the limited amount of trans stuff. Jesse is the only one I know doing some sort of adapter.
When my project is a little more firm I will reveal what I am doing and let the nay sayers tear it apart.
Bondo Bob also does adaptors, My buddy used one of his and it worked flawlessly.
Posted By: B3422W5
Re: How good are the P7 engines for drag racing? - 04/09/12 04:37 PM
Quote:Quote:Quote:Quote:
The best( and about only) example of a P7 motor drag racing on this forum was my buddies 68 Dart he raced all summer, year before last.
Wow, a little arrogant there.. Just cause I don't race asphalt, I'm not good enough to be an example??? I'm glad your BUDDY is the only one GOOD enough to be taken into consideration in this forum... Just another example of all you clicky azzholes on here... IF you don't drag race assphalt you're no good...
Last i checked this is a drag racing forum. I wasnt trying to be arrogant, just stating a fact, he actually raced one a whole season. Only person i know who has done so.
Lighten up dude, i didnt say he was good, bad or indifferent, just said he raced it, and posted his basic combo and what it ran.
Your ice racing deal has zero to do with this forum, unless they changed it from drag racing.
I have posted on here for 10 years, go pack sand.
Are you kidding me?? I know it's a drag racing forum you frickin Douche. How is drag racing on ice not drag racing??? Please tell me sir why I don't qualify? Sorry my 7 years isn't good enough for your 10.. Once again you go with I'm bigger and better then you...
And I have 3 seasons drag racing on mine...
So now i am a douche for posting facts on a post somebody besides you started.
I can only speak for myself, but i could care less about ice racing, nothing against you, but i dont see what it has to do with this forum.
If we were going to talk about R5P7 stuff, guess we could read old Busch/Nascar forums as well, but like ice racing they dont interest me, not probably do they interest the original poster, who i am quite sure wanted to know who had drag raced a a p7 deal.
Posted By: DemonDust
Re: How good are the P7 engines for drag racing? - 04/09/12 04:57 PM
No you are a douche because you are telling me things I already know.
1. The OP asked how they are for drag racing. (I answered because I drag race)
2. You tell me this is a drag racing site. ( I know that's why I posted here.)
3. Again you proceed to tell me about drag racing and this site and the OP wanting to know about drag racing a R5P7.. ( and again I understood this before you explained to me the last 3 times, like I'm a 5 year old.)
So please sir once again I'm asking how does what I do not pertain to the OP or this site?
1. The OP asked how they are for drag racing. (I answered because I drag race)
2. You tell me this is a drag racing site. ( I know that's why I posted here.)
3. Again you proceed to tell me about drag racing and this site and the OP wanting to know about drag racing a R5P7.. ( and again I understood this before you explained to me the last 3 times, like I'm a 5 year old.)
So please sir once again I'm asking how does what I do not pertain to the OP or this site?
Posted By: camastomcat
Re: How good are the P7 engines for drag racing? - 04/09/12 05:02 PM
Quote:\
No you are a douche because you are telling me things I already know.
1. The OP asked how they are for drag racing. (I answered because I drag race)
2. You tell me this is a drag racing site. ( I know that's why I posted here.)
3. Again you proceed to tell me about drag racing and this site and the OP wanting to know about drag racing a R5P7.. ( and again I understood this before you explained to me the last 3 times, like I'm a 5 year old.)
So please sir once again I'm asking how does what I do not pertain to the OP or this site?
You're right, it is kinda clickish here, and I for one am a fan of ice racing. I wish they showed more of it on TV. Good luck on the asphalt! PS I'm also a fan of the bad boy small block crowd of which you are one.
Posted By: Adrielp
Re: How good are the P7 engines for drag racing? - 04/09/12 05:07 PM
All of the info posted on people's experience with this engine is relevant. Just remember opinions are opinions. What each person deems important in terms of the drag racing world is individually based. There's no need to argue or discredit one's post. I say agree to disagree and keep it moving.
Posted By: DemonDust
Re: How good are the P7 engines for drag racing? - 04/09/12 05:29 PM
Sorry Adriel, Didn't mean to hijack your post. It's just that arrogant comment set me off that none of the other posters were good enough, besides that one. I hope you get the info you need. If you have any specifics don't be afarid to ask. I still have my car and more than one engine that I personally built. So I can try to answer any tech questions about the internals you may have.
Posted By: produster
Re: How good are the P7 engines for drag racing? - 04/09/12 05:48 PM
Quote:Quote:
The one down fall I have heard on these motors is the valve stem size and running a bigger spring pressure for bigger cam for drag racing. But I know they, valve guides can be made bigger.
I think that is the biggest down fall of these motors for drag racing. A cam change, better intake, bigger carb, a little off the head to up the compression and you can look in upwards of 1000hp. If given the time and effort you could have a killer set up.
Only issue is the limited amount of trans stuff. Jesse is the only one I know doing some sort of adapter.
When my project is a little more firm I will reveal what I am doing and let the nay sayers tear it apart.
Bondo Bob also does adaptors, My buddy used one of his and it worked flawlessly.
I am not going to run an automatic. I am actually going to row.
Posted By: Al_Alguire
Re: How good are the P7 engines for drag racing? - 04/09/12 05:55 PM
I think we need a group hug here
This is a RACE forum, not just drag racing. We have drag racers, ice drag racers, boat racers, truck pullers, and some roundy round guys in here. It is a forum for all RACERS. Everyone is entitiled to thier opinion and those opinions are how we learn.
So let's see if we can get back on topic here please.
Now dont make me get out the
Hate to see this be the first time I axe a good topic on Moparts
This is a RACE forum, not just drag racing. We have drag racers, ice drag racers, boat racers, truck pullers, and some roundy round guys in here. It is a forum for all RACERS. Everyone is entitiled to thier opinion and those opinions are how we learn.
So let's see if we can get back on topic here please.
Now dont make me get out the
Hate to see this be the first time I axe a good topic on Moparts
Posted By: BB70DUSTER
Re: How good are the P7 engines for drag racing? - 04/09/12 08:58 PM
Quote:
I think we need a group hug here
This is a RACE forum, not just drag racing. We have drag racers, ice drag racers, boat racers, truck pullers, and some roundy round guys in here. It is a forum for all RACERS.
You forgot the Sand drag guy Al... LOL
Posted By: produster
Re: How good are the P7 engines for drag racing? - 04/09/12 09:08 PM
Quote:Quote:
I think we need a group hug here
This is a RACE forum, not just drag racing. We have drag racers, ice drag racers, boat racers, truck pullers, and some roundy round guys in here. It is a forum for all RACERS.
You forgot the Sand drag guy Al... LOL
Isn't there a boat racer here too? that dude is CRAZY!!!
Posted By: jim sciortino
Re: How good are the P7 engines for drag racing? - 04/09/12 09:20 PM
Quote:I'll hug the women.
I think we need a group hug here
Posted By: CompWedgeEngines
Re: How good are the P7 engines for drag racing? - 04/09/12 11:16 PM
Great job Jim...always willing to take a bullet for the team...
Posted By: jim sciortino
Re: How good are the P7 engines for drag racing? - 04/09/12 11:20 PM
Quote:Somebody has to.
Great job Jim...always willing to take a bullet for the team...
Posted By: Hot 340
Re: How good are the P7 engines for drag racing? - 04/09/12 11:24 PM
Posted By: DemonDust
Re: How good are the P7 engines for drag racing? - 04/09/12 11:46 PM
If you are planning on putting it in a car you will have to modify the k frame for sure. You will have to find a place to stuff a 1.5 gallon oil tank, remote filter, and (8) different size AN lines flowing everywhere. Build custom headers. Mount the motor plate and get an adapter for a trans.
I drove mine on the street for short trips with no problems as well.
I drove mine on the street for short trips with no problems as well.
Posted By: produster
Re: How good are the P7 engines for drag racing? - 04/10/12 12:03 AM
Quote:
If you are planning on putting it in a car you will have to modify the k frame for sure. You will have to find a place to stuff a 1.5 gallon oil tank, remote filter, and (8) different size AN lines flowing everywhere. Build custom headers. Mount the motor plate and get an adapter for a trans.
I drove mine on the street for short trips with no problems as well.
true getting into a stock eng compartment will be a chore. You look like you have a nice clean installation.
I will be lucky, tube car....
Posted By: LA360
Re: How good are the P7 engines for drag racing? - 04/10/12 12:09 AM
Quote:Quote:Maybe that much in Oz with all of the shipping charges you guys have to endure, but my friend in the dragster has less than $20K in his and almost $6K was in the Engler Fuel Injection, and dry sump system. I forgot to mention, they don't have have any provision for wet-sump oiling, so dry-sump is a necessity.
An all out engine is going to cost plenty of $$$, you're not going to get any change out of $60-80K
Using ex Nascar pieces will save you a ton of $$$$, but I was referring to an engine from a Comp Elim style engine builder using new parts. The top end alone will eat up $10-20K. Price up a SB2.2 engine at Patterson's or Rick Watters and you will see what I mean
Posted By: 40ford
Re: How good are the P7 engines for drag racing? - 04/10/12 02:19 AM
Here are our specs for the P7
225" tuttle FED
1370lbs total in the water
358" 3.25 stroke, 4.195 bore
296/302 @.050, 830 IN 785 EX (at the valve) 115.5 LS
*Heads are later Evernham versions with a little "massaging" for alcohol happiness by Chad Speier. Straight nascar pull offs are great with gas not enough volume for alky.
*Engler mechanical straight port injection 2.900" (He was an extreme help!)
*MSD pro mag (electronic msd 7AL-3 didn't like 10,000+)
*GRP aluminum rods. Small flat dome (.050) 14:1 Comp.
*It has been pretty much a maintenance free piece and extremely consistent. As said earlier the parts are out there some good some not so good as is the case with any engine combo. The basic engine was what we had left after hanging up our round track shoes. Also, Kent Ritter has been and still is extremely helpful with advice and or parts! So far the engine's best times are:
1.06--60'
4.69---1/8
7.40---1/4
These were at 3900' (if i remember correct, haven't run since last summer)
launch @ 7000
shift @ 9600
thru the traps @ 10400
Definitely a screamer through short zoomies!
225" tuttle FED
1370lbs total in the water
358" 3.25 stroke, 4.195 bore
296/302 @.050, 830 IN 785 EX (at the valve) 115.5 LS
*Heads are later Evernham versions with a little "massaging" for alcohol happiness by Chad Speier. Straight nascar pull offs are great with gas not enough volume for alky.
*Engler mechanical straight port injection 2.900" (He was an extreme help!)
*MSD pro mag (electronic msd 7AL-3 didn't like 10,000+)
*GRP aluminum rods. Small flat dome (.050) 14:1 Comp.
*It has been pretty much a maintenance free piece and extremely consistent. As said earlier the parts are out there some good some not so good as is the case with any engine combo. The basic engine was what we had left after hanging up our round track shoes. Also, Kent Ritter has been and still is extremely helpful with advice and or parts! So far the engine's best times are:
1.06--60'
4.69---1/8
7.40---1/4
These were at 3900' (if i remember correct, haven't run since last summer)
launch @ 7000
shift @ 9600
thru the traps @ 10400
Definitely a screamer through short zoomies!
Posted By: DemonDust
Re: How good are the P7 engines for drag racing? - 04/10/12 02:59 AM
Quote:Quote:
If you are planning on putting it in a car you will have to modify the k frame for sure. You will have to find a place to stuff a 1.5 gallon oil tank, remote filter, and (8) different size AN lines flowing everywhere. Build custom headers. Mount the motor plate and get an adapter for a trans.
I drove mine on the street for short trips with no problems as well.
true getting into a stock eng compartment will be a chore. You look like you have a nice clean installation.
I will be lucky, tube car....
Tube car will be great! Lots of room and super light!! Should be an easy high 8 car.
Posted By: DemonDust
Re: How good are the P7 engines for drag racing? - 04/10/12 03:04 AM
Quote:
Here are our specs for the P7
225" tuttle FED
1370lbs total in the water
358" 3.25 stroke, 4.195 bore
296/302 @.050, 830 IN 785 EX (at the valve) 115.5 LS
*Heads are later Evernham versions with a little "massaging" for alcohol happiness by Chad Speier. Straight nascar pull offs are great with gas not enough volume for alky.
*Engler mechanical straight port injection 2.900" (He was an extreme help!)
*MSD pro mag (electronic msd 7AL-3 didn't like 10,000+)
*GRP aluminum rods. Small flat dome (.050) 14:1 Comp.
*It has been pretty much a maintenance free piece and extremely consistent. As said earlier the parts are out there some good some not so good as is the case with any engine combo. The basic engine was what we had left after hanging up our round track shoes. Also, Kent Ritter has been and still is extremely helpful with advice and or parts! So far the engine's best times are:
1.06--60'
4.69---1/8
7.40---1/4
These were at 3900' (if i remember correct, haven't run since last summer)
launch @ 7000
shift @ 9600
thru the traps @ 10400
Definitely a screamer through short zoomies!
I have pretty much the same build as you. Except the injection. Looks like I should be shifting a bit higher. I was doing 1-2 at 8400 and 2-3 at 8800. My stall is 7200.. I'm gonna hit the asphalt this summer can't wait to try the higher shift points
Posted By: 40ford
Re: How good are the P7 engines for drag racing? - 04/10/12 03:25 AM
I think you may find it gets another set of "legs" up there. These engines will take lots of abuse under some pretty adverse conditions. We run ours completely dry of water and have made three quarter mile passes within 20 minutes in 90+ degree heat with bracket like consistency. Although they dont make the torque that a lot of engines will, they will however made good power upstairs and allow a racer to use torque multiplier instead. We run a 5.0 gear and 31" tire and use a 1.65 first gear ratio in the glide. I cant imagine racing on the ice (my hat's off to ya) good luck on the pavement!
Posted By: Adrielp
Re: How good are the P7 engines for drag racing? - 04/10/12 04:21 AM
All of the post have been very informative. I think this might be the best starter option for what I wanna do in the future. I'm quite aways off from building anything but I my degrees are finally within reach(I graduate from college in Dec). Depending upon whether I go grad school or straight into the workforce will determine how quickly I can start building something. I'm still trying to determine whether I should start out building a car or converting the car we have. Both, would be quite a bit of work.
This engine looks to have very good potential for power. Getting a properly spec out cam, new valvetrain parts, and reworking the heads some would be key. 10000rpm should be cake after that. I think adjustments could be made in other areas to work well plus with the money you save getting a complete engine, you could put that money back into the engine to upgrade other things. I would also have to change the oil system over to wet sump to work in this class as well but thats doable. Anybody know what the max bore is on the R5 block?
This engine looks to have very good potential for power. Getting a properly spec out cam, new valvetrain parts, and reworking the heads some would be key. 10000rpm should be cake after that. I think adjustments could be made in other areas to work well plus with the money you save getting a complete engine, you could put that money back into the engine to upgrade other things. I would also have to change the oil system over to wet sump to work in this class as well but thats doable. Anybody know what the max bore is on the R5 block?
Posted By: LA360
Re: How good are the P7 engines for drag racing? - 04/10/12 05:09 AM
4.25" on the right block
If 10K RPM was "cake", everyone would be doing it.
If 10K RPM was "cake", everyone would be doing it.
Posted By: Al_Alguire
Re: How good are the P7 engines for drag racing? - 04/10/12 06:43 AM
40Ford what kind of valespring life do you get at that RPM?
Posted By: Adrielp
Re: How good are the P7 engines for drag racing? - 04/10/12 11:18 AM
Quote:
40Ford what kind of valespring life do you get at that RPM?
After talking with a few comp guys, they have told me that when your spinning these motors at full tilt, you can get about 6 passes on a set of springs. Also, i don't want to make it sound like 10K is just that easy, but rather it is possible to achieve and be efficient in comparison to other engines spinning that much rpm. In a SS/AM application, you wouldn't run the motor quite as hard so you could probably expect much more spring life at a lower rpm. I would imagine the fatigue life of a spring at over 10K vs. that at 9500 and below are very different.
Posted By: 40ford
Re: How good are the P7 engines for drag racing? - 04/10/12 02:37 PM
Everybody sit down, take a deep breath, forget most of what you have heard----and listen to what we do!
We use PAC valve springs, 1.500" in diameter, good to .900" lift. Seat pressure is 400, 1280 open. If you notice, we only go to .830" on the intake at the valve, even less on the exhaust. We do use 1/2" pushrods. Spring life so far last year was 48 passes---the springs still check out fine!
We don't try to get into that 1.000" lift range. Why? The heads still flow well----but not that much better than at .750" Why use crazy valve lifts when it doesn't give you that much more? Also, we preheat the oil---and keep it at 200 degrees for every run. Also, we use spring oilers---absolute necessary for decent valve spring life(take a lesson from the roundy round guys). And, after evey race weekend, we release valve spring pressure.
The P7 is a fine engine, short stroke, big bore. It doesn't have the torque that larger engines do but that is a matter of mechanical advantage. Yes, we probably get our little 358" to go a little faster/quicker----but it can get expensive real quick. For what it does, we are very happy. You have no idea how happy we are when we trailer a 500" supercharged BB FED with our little engine. And we are happy when our "friendly" competitors just shake their heads when they look at it!
We use PAC valve springs, 1.500" in diameter, good to .900" lift. Seat pressure is 400, 1280 open. If you notice, we only go to .830" on the intake at the valve, even less on the exhaust. We do use 1/2" pushrods. Spring life so far last year was 48 passes---the springs still check out fine!
We don't try to get into that 1.000" lift range. Why? The heads still flow well----but not that much better than at .750" Why use crazy valve lifts when it doesn't give you that much more? Also, we preheat the oil---and keep it at 200 degrees for every run. Also, we use spring oilers---absolute necessary for decent valve spring life(take a lesson from the roundy round guys). And, after evey race weekend, we release valve spring pressure.
The P7 is a fine engine, short stroke, big bore. It doesn't have the torque that larger engines do but that is a matter of mechanical advantage. Yes, we probably get our little 358" to go a little faster/quicker----but it can get expensive real quick. For what it does, we are very happy. You have no idea how happy we are when we trailer a 500" supercharged BB FED with our little engine. And we are happy when our "friendly" competitors just shake their heads when they look at it!
Posted By: produster
Re: How good are the P7 engines for drag racing? - 04/10/12 03:07 PM
Quote:Quote:Quote:
If you are planning on putting it in a car you will have to modify the k frame for sure. You will have to find a place to stuff a 1.5 gallon oil tank, remote filter, and (8) different size AN lines flowing everywhere. Build custom headers. Mount the motor plate and get an adapter for a trans.
I drove mine on the street for short trips with no problems as well.
true getting into a stock eng compartment will be a chore. You look like you have a nice clean installation.
I will be lucky, tube car....
Tube car will be great! Lots of room and super light!! Should be an easy high 8 car.
Better be faster than that or I will not be happy.
Posted By: Al_Alguire
Re: How good are the P7 engines for drag racing? - 04/10/12 03:45 PM
40Ford, Thanks for the info. I was curious with the valve weights and lift what kind of life you were getting. We spin our 99 a little less RPM but with more lift and obviously much heavier valves. I also use Pac springs and we never leave the rockers on the car. We just switched to a heavier spring and so far seem to have better valve spring life, I am sure soon we will find the limits of them however.
I to am contemplating building one fo these engines. I just cannot seem to find the good guy deals like some I have heard of on the hard parts. Not worried about consumables as we will replace most of those anywya in building an engine.
I to am contemplating building one fo these engines. I just cannot seem to find the good guy deals like some I have heard of on the hard parts. Not worried about consumables as we will replace most of those anywya in building an engine.
Posted By: 40ford
Re: How good are the P7 engines for drag racing? - 04/10/12 06:53 PM
I understand your difficulty about getting some of the "sweetheart" deals on P7 engines. Kent Ridder helped us to get the first one. Since then, there are other sources out there: Ernie Elliot, Evernham,and I understand that Penske still has some. I was not impressed with Davis or Petty engines. Sorry, but that is my honest opinion. You just need to keep your "ears to the ground" and one will be available. I prefer to know the exact background of a used engine, who built it and for what purpose. For example, some of these "deal" are for old experimental engines---sometimes you need to be careful of these because the heads may not be that good, etc.
I have heard of engines that sell for $4K complete. I preferred to get an Elliot engine that was a truck engine---It had a roller cam/lifters and set up for the Nascar 830 CFM carb. Restrictor plate engines often are built very different. The old Busch engines have rollers----but used the 390 carb. Of course, Cup engines are flat tappet.
Back to the valve springs----you would be surprised at the difference spring oilers and preheated oil makes on valve spring life.
I have heard of engines that sell for $4K complete. I preferred to get an Elliot engine that was a truck engine---It had a roller cam/lifters and set up for the Nascar 830 CFM carb. Restrictor plate engines often are built very different. The old Busch engines have rollers----but used the 390 carb. Of course, Cup engines are flat tappet.
Back to the valve springs----you would be surprised at the difference spring oilers and preheated oil makes on valve spring life.
Posted By: 23T Hemmee
Re: How good are the P7 engines for drag racing? - 04/10/12 09:54 PM
Quote:Reminds me of the old "battleship springs on the Hemi's in the early 70's, if you even wacked the throttle one time before head temp was 180*, more than likely you broke a spring....
Back to the valve springs----you would be surprised at the difference spring oilers and preheated oil makes on valve spring life.
Posted By: jg309
Re: How good are the P7 engines for drag racing? - 04/11/12 11:50 PM
thats it give it to him duster,adrielp give me a call & i'll help you with what i can jg309,618-806-1564,got a deal for you
Posted By: Adrielp
Re: How good are the P7 engines for drag racing? - 04/12/12 02:19 AM
Quote:
thats it give it to him duster,adrielp give me a call & i'll help you with what i can jg309,618-806-1564,got a deal for you
It must be some deal lol, I am a college student. I will try to give you a call Friday before noon.
Posted By: Al_Alguire
Re: How good are the P7 engines for drag racing? - 04/12/12 04:39 AM
Well we do pre heat the oil. Np spray bars however, just a pushrod oiled deal. Dont now of anyone running a 99Hemi with spraybars.
Posted By: 40ford
Re: How good are the P7 engines for drag racing? - 04/12/12 02:18 PM
Al, I understand there is a difference between "spray bars" and "spring oilers". I understand the "spray bars" oil the rockers primarily. "Spring oilers" are tubes welded inside the valve covers that spray oil directly on to the valve springs. We began doing this during our oval track days(20 years ago)---it worked for us---still do it on our drag engines. As Ronny said, they help to prevent spring breakage during warm up. BTW, some people(including the Direct Connection people) thought we were crazy for wanting to build "spring oilers"
We have never used "spray bars".
We have never used "spray bars".
Posted By: Georg
Re: How good are the P7 engines for drag racing? - 04/13/12 06:36 AM
40ford - I sent you e-mail. Did you got it?
Posted By: 40ford
Re: How good are the P7 engines for drag racing? - 04/13/12 03:12 PM
No, I didn't get the message. Feel free to ask the question on the general board.
Charles
Charles
Posted By: Georg
Re: How good are the P7 engines for drag racing? - 04/13/12 10:15 PM
Posted By: Leon441
Re: How good are the P7 engines for drag racing? - 04/13/12 10:33 PM
Well the one I was thinking of buying got sold to someone in CANADA. I just have too much going on to buy one at the moment. Also still need to sell my R3 shorblock to have some more cash.
I really want the EEI block with taller deck and 340 mains. I beleive the EEI heads are much better than any of the Everham heads. I have two sets of Everham heads. Bondobob has a set of Bill Davis heads that are big.
40Ford do you know of any EEI truck stuff for sale? Really would rather have a roller to start with.
Leon
I really want the EEI block with taller deck and 340 mains. I beleive the EEI heads are much better than any of the Everham heads. I have two sets of Everham heads. Bondobob has a set of Bill Davis heads that are big.
40Ford do you know of any EEI truck stuff for sale? Really would rather have a roller to start with.
Leon
Posted By: jg309
Re: How good are the P7 engines for drag racing? - 04/14/12 02:01 AM
leon give me a call tomorrow morning at 618-806-1564,what kind of r3 stouf you got,maybe do some trading got a new xr2 & all the goddies to go with it,jg309
Posted By: Adrielp
Re: How good are the P7 engines for drag racing? - 04/15/12 03:02 PM
So what are the key differences in the head and engine that make them unable to be used correctly for drag racing? Also, what work is involved to change the engine over to a roller? With the ability to use epoxy, I would think you be able to get the port shape back to whatever you wanted. Also, one would be replacing most of the valvetrain anyway. Also, since there is less meat on the intake port side, has anyone thought of welding the top of the intake ports a certain amount, then re-machining spring seats and rocker stands, you would just longer pushrods after that correct? I figure you could get a .25 to .375 more height in the port.
Posted By: mloboda
Re: How good are the P7 engines for drag racing? - 04/15/12 05:01 PM
"...shift @ 9600
thru the traps @ 10400..."
May I ask what was the brand and life of your valve springs ?
thru the traps @ 10400..."
May I ask what was the brand and life of your valve springs ?
Posted By: Leon441
Re: How good are the P7 engines for drag racing? - 04/15/12 07:39 PM
There is really nothin short in these engines as far as making them a drag race engine. If you want a really aggressive roller cam you need to either convert over or buy a truck or busch engine. The intake valve to exhaust ratio is a little different but, read most of the combos on here they are typically the same as the P7 engines.
Most sportsman drag racers are after big inch engines that don't have to turn real hard. The reason was engines of the past hurt parts when you really zinged on them. They got expensive. These engines basically live forever at high RPM. They don't make the 600 HP of years past but over 800 HP.
Then you get the guy who says the engines have no torque. And look they are running a 408 with nothing heads and no gear ratio. These 408 combos can easily make 600 lbs of torque but run out of air and barely break 600 HP in any adverse air conditions. So when a guy like Bondbob comes out and blast a 5.9 et shifting like a daily driven street car everybody makes excuses for how he misteriously done it. There is no excuse it is simply HP and he hadn't even used it yet. Shifting an engine that only makes 550 torque at 6200. Well he was just starting to see over 700 HP. He had some bad luck and broke a spring now everyone got scared off. Those engines prefer to be shifted at 9,500. That 5.9 ET just turned into at least a 5.50.
I simply want the best of both worlds. An XR or a EEI block and lets pack some stroke under these heads and turn 9,500. SLOW economy and no one buying anything. That is the reason I don't have one and that is the reason others have not either.
Most sportsman drag racers are after big inch engines that don't have to turn real hard. The reason was engines of the past hurt parts when you really zinged on them. They got expensive. These engines basically live forever at high RPM. They don't make the 600 HP of years past but over 800 HP.
Then you get the guy who says the engines have no torque. And look they are running a 408 with nothing heads and no gear ratio. These 408 combos can easily make 600 lbs of torque but run out of air and barely break 600 HP in any adverse air conditions. So when a guy like Bondbob comes out and blast a 5.9 et shifting like a daily driven street car everybody makes excuses for how he misteriously done it. There is no excuse it is simply HP and he hadn't even used it yet. Shifting an engine that only makes 550 torque at 6200. Well he was just starting to see over 700 HP. He had some bad luck and broke a spring now everyone got scared off. Those engines prefer to be shifted at 9,500. That 5.9 ET just turned into at least a 5.50.
I simply want the best of both worlds. An XR or a EEI block and lets pack some stroke under these heads and turn 9,500. SLOW economy and no one buying anything. That is the reason I don't have one and that is the reason others have not either.
Posted By: mafo
Re: How good are the P7 engines for drag racing? - 04/15/12 10:05 PM
a friend of mine have a p7 motor in his valiant, will be ready this summer, I will post up some results later, this is a real streeter with leaf springs and all...
I tested one of his heads on my bench and it was one of the best small block heads I have seen, right on par with my cfe w8 s on high lifts and actually a bit better on low lifts
with the short stroke I think the converter is going to be critical but I see no reason why this shouldn t work, I can see 8 sec potential in the right car, and that for less money than I have in the heads
I tested one of his heads on my bench and it was one of the best small block heads I have seen, right on par with my cfe w8 s on high lifts and actually a bit better on low lifts
with the short stroke I think the converter is going to be critical but I see no reason why this shouldn t work, I can see 8 sec potential in the right car, and that for less money than I have in the heads
Posted By: LA360
Re: How good are the P7 engines for drag racing? - 04/15/12 11:36 PM
Quote:
So what are the key differences in the head and engine that make them unable to be used correctly for drag racing? Also, what work is involved to change the engine over to a roller? With the ability to use epoxy, I would think you be able to get the port shape back to whatever you wanted. Also, one would be replacing most of the valvetrain anyway. Also, since there is less meat on the intake port side, has anyone thought of welding the top of the intake ports a certain amount, then re-machining spring seats and rocker stands, you would just longer pushrods after that correct? I figure you could get a .25 to .375 more height in the port.
I really don't get where this misconception that a P7 headed engine won't make a good drag engine, I can only put it down to the fact that the people making these statements know nothing about what goes into a Comp eliminator style engine. There are plenty of SB2.2 and Chevy Splayed valve engines making big power, the P7 deal would be no different.
Leon made some very good points also.
Posted By: moeflo
Re: How good are the P7 engines for drag racing? - 04/16/12 01:02 AM
Quote:
? With the ability to use epoxy, I would think you be able to get the port shape back to whatever you wanted. Also, one would be replacing most of the valvetrain anyway. Also, since there is less meat on the intake port side, has anyone thought of welding the top of the intake ports a certain amount, then re-machining spring seats and rocker stands, you would just longer pushrods after that correct? I figure you could get a .25 to .375 more height in the port.
I don't think you'd need to weld on these to allow raising the port. It weakens the head, and these heads already have ports high enough for you to be well into the "diminishing-returns" zone. They just don't require much re-engineering unless you are involved in all out ($$$) racing.
Sanborn..you're my hero. Never has so much 1st hand experience with detailed know-how (+ engineering based analysis if required) along with the willingness to share been around for Dodge guys.
Posted By: 40ford
Re: How good are the P7 engines for drag racing? - 04/16/12 03:50 PM
Moe, good to hear from you! I'm no hero----although I do still have the scars from the arrows in my back---some old wounds go back 30 years or more.
A little more about the P7 heads----We have a set of Ernie Elliot heads, a set of Evernham heads and a set of Davis heads. The Elliot and Evernham heads are close---especially for gas. The Davis heads I was not impressed with---for gas(without a lot of rework). The Elliot and Evernham heads both were subjected to a CNC "lightening" program which removed a lot of material around the intake port. So they are somewhat limited as to future enlarging. The Davis heads didn't have the "lightening" program, so a lot of material remains for enlargement.
We run methanol---which needs different work for best performance. The intake/exhaust flow ratios are different. We chose to use the Evernham heads because they flowed better out of the box and the "lightening" program wasn't as aggressive which allowed more work on the intake runners. After rework, the Evernham (modified for methanol) flowed 407CFM @ .400" and 422CFM @ .800" and didn't stall up to 1.000". These numbers are with the standard 2.185" intake valve with 11/32" stems.
We run a nostalgia FED----so we have self limited ourselves with modifications, money spent, etc. If we had a desire to spend a lot of more money, the Davis heads can have much larger intake runners, but need much larger valves to take advantage of the larger runners. And we limited ourselves to .800" lift valve lift for good spring life. There is a lot of flow in the "non lightened" Davis heads BUT be prepared to spend some money and be prepared to buzz the engine higher. With our current setup, 7.40s are easily attainable----the car is capable of 7.00s but it takes more inches, more head flow and more cam lift. We just don't choose to do it!
There are many different versions of the P7 engine depending on the builder, and the track the engine was designed for. Numerous head programs, different camshaft selections, etc., are all awaiting a buyer of a "obsolete" P7 engine. The engines were designed for use in Nascar and race gas. Drag race applications do require changes especially for a light car like ours. An example for desired drag race changes-----we would really like or lobe separation( have 115 1/2 degrees) but more require a "custom", billet core---with a significant cost. We choose to not bear the extra cost.
A little more about the P7 heads----We have a set of Ernie Elliot heads, a set of Evernham heads and a set of Davis heads. The Elliot and Evernham heads are close---especially for gas. The Davis heads I was not impressed with---for gas(without a lot of rework). The Elliot and Evernham heads both were subjected to a CNC "lightening" program which removed a lot of material around the intake port. So they are somewhat limited as to future enlarging. The Davis heads didn't have the "lightening" program, so a lot of material remains for enlargement.
We run methanol---which needs different work for best performance. The intake/exhaust flow ratios are different. We chose to use the Evernham heads because they flowed better out of the box and the "lightening" program wasn't as aggressive which allowed more work on the intake runners. After rework, the Evernham (modified for methanol) flowed 407CFM @ .400" and 422CFM @ .800" and didn't stall up to 1.000". These numbers are with the standard 2.185" intake valve with 11/32" stems.
We run a nostalgia FED----so we have self limited ourselves with modifications, money spent, etc. If we had a desire to spend a lot of more money, the Davis heads can have much larger intake runners, but need much larger valves to take advantage of the larger runners. And we limited ourselves to .800" lift valve lift for good spring life. There is a lot of flow in the "non lightened" Davis heads BUT be prepared to spend some money and be prepared to buzz the engine higher. With our current setup, 7.40s are easily attainable----the car is capable of 7.00s but it takes more inches, more head flow and more cam lift. We just don't choose to do it!
There are many different versions of the P7 engine depending on the builder, and the track the engine was designed for. Numerous head programs, different camshaft selections, etc., are all awaiting a buyer of a "obsolete" P7 engine. The engines were designed for use in Nascar and race gas. Drag race applications do require changes especially for a light car like ours. An example for desired drag race changes-----we would really like or lobe separation( have 115 1/2 degrees) but more require a "custom", billet core---with a significant cost. We choose to not bear the extra cost.
Posted By: Georg
Re: How good are the P7 engines for drag racing? - 04/18/12 07:00 PM
40ford - I sended you mail in pm also this time. Maybe your box is full? Just that my mail is too long to discuss it here
Thanks
Georg
Thanks
Georg
Posted By: Adrielp
Re: How good are the P7 engines for drag racing? - 04/18/12 08:24 PM
Quote:
Moe, good to hear from you! I'm no hero----although I do still have the scars from the arrows in my back---some old wounds go back 30 years or more.
A little more about the P7 heads----We have a set of Ernie Elliot heads, a set of Evernham heads and a set of Davis heads. The Elliot and Evernham heads are close---especially for gas. The Davis heads I was not impressed with---for gas(without a lot of rework). The Elliot and Evernham heads both were subjected to a CNC "lightening" program which removed a lot of material around the intake port. So they are somewhat limited as to future enlarging. The Davis heads didn't have the "lightening" program, so a lot of material remains for enlargement.
We run methanol---which needs different work for best performance. The intake/exhaust flow ratios are different. We chose to use the Evernham heads because they flowed better out of the box and the "lightening" program wasn't as aggressive which allowed more work on the intake runners. After rework, the Evernham (modified for methanol) flowed 407CFM @ .400" and 422CFM @ .800" and didn't stall up to 1.000". These numbers are with the standard 2.185" intake valve with 11/32" stems.
We run a nostalgia FED----so we have self limited ourselves with modifications, money spent, etc. If we had a desire to spend a lot of more money, the Davis heads can have much larger intake runners, but need much larger valves to take advantage of the larger runners. And we limited ourselves to .800" lift valve lift for good spring life. There is a lot of flow in the "non lightened" Davis heads BUT be prepared to spend some money and be prepared to buzz the engine higher. With our current setup, 7.40s are easily attainable----the car is capable of 7.00s but it takes more inches, more head flow and more cam lift. We just don't choose to do it!
There are many different versions of the P7 engine depending on the builder, and the track the engine was designed for. Numerous head programs, different camshaft selections, etc., are all awaiting a buyer of a "obsolete" P7 engine. The engines were designed for use in Nascar and race gas. Drag race applications do require changes especially for a light car like ours. An example for desired drag race changes-----we would really like or lobe separation( have 115 1/2 degrees) but more require a "custom", billet core---with a significant cost. We choose to not bear the extra cost.
Thanks for the info! I think the majority of guys thinking about drag racing these engines would know that they would need to get a camshaft designed to take full advantage of the potential power. How big is the cam core in these engines. I saw a set of rockers arms on line that were 2.0 ratio. Thats a lot of pressure being applied to the camshaft. A bigger cam core might be better assuming there's room for it.
Posted By: produster
Re: How good are the P7 engines for drag racing? - 04/18/12 08:45 PM
It is a 60mm cam.
Posted By: AndyF
Re: How good are the P7 engines for drag racing? - 04/18/12 09:35 PM
Edelbrock is giving away P7 intake manifolds. Regular price is $740, sales price is $140.
So if anyone is going to build a P7 engine and they want a new intake manifold, now might be a good time to grab one.
So if anyone is going to build a P7 engine and they want a new intake manifold, now might be a good time to grab one.
Posted By: produster
Re: How good are the P7 engines for drag racing? - 04/18/12 11:14 PM
That is a good price. Too bad I am going to run a 2x4
Posted By: LA360
Re: How good are the P7 engines for drag racing? - 04/19/12 03:03 AM
Quote:
Edelbrock is giving away P7 intake manifolds. Regular price is $740, sales price is $140.
So if anyone is going to build a P7 engine and they want a new intake manifold, now might be a good time to grab one.
Got a link?
Posted By: Triple Threat
Re: How good are the P7 engines for drag racing? - 04/19/12 03:09 AM
Posted By: 40ford
Re: How good are the P7 engines for drag racing? - 04/19/12 05:05 PM
A little more on P7 engines. First, please understand what these engines were designed for. They were designed for NASCAR racing only, not drag racing.
In NASCAR, there are three touring series; Cup, Busch and Truck.
The rules are different for each class. The Cup engines are FLAT TAPPET ONLY. That is where the extreme rocker ratios come from(to to 2.1 to 1). On a flat tappet cam, you can use a high ratio rocker and get better area under the lift curve. Also, with flat tappet cams, you use lower pressure springs----the high ratio rockers will last, at least for one race and that is all an engine builder cares about. After the race is over, the rockers go in the trash.
The truck and Busch engines both use roller cams with high spring pressures. You don't see rocker ratios higher than 1.80 to 1. But, the heads and cams are different for the two classes. Busch uses a 390 CFM Holley type carb, thus the cams are smaller and oftentimes the heads are too. The truck engines use 830CFM Holley type carbs and oftentimes the heads are bigger too.
I mention the Holley TYPE carbs because many are not Holley carbs but Titanium billet "lookalikes". They weigh less than two pounds and cost bigs $$$. That is the reason you never see any on the used market and the few you see are dyno carbs. That may change since NASCAR is converting to injection but none of the big $$$ carbs are on the market yet.
Now, lets talk about general cylinder head rules----NASCAR specs valve size(not stem size), valve angles, intake port centerline specs and intake port square inch areas. Most NASCAR engine builders machine away any excess aluminum(weight) around the intake runners---since the size of the runner is spec'd. Therefore for drag racing, there may not be a lot of excess "meat" available around the intake runners. You see a lot of heads with smaller MM size valve stems----these are generally one race valves. Guess what happens to the valves after the race-----trash can! Same with springs, sometimes retainers, titanium shoulder locks, etc. One note----the springs take a specific retainer and titanium shoulder lock. You get into trouble if you don't match the spring to the retainer and the lock.
Now about the cast iron blocks, They are 9.00" deck blocks, same a SB GMs. And, the blocks are big bore(up to 4.185") but short stroke, around 3.25". The main bearing saddles are for a 2.25" Ford type bearing. Only the Elliot aluminum blocks are for a larger 2.50" main bearing. You can easily get a longer stroke crank---all you do is buy a custom billet crank---up to about 3.625" for a 9" deck iron block. And you can bore the blocks larger---but where do you find the deck plates? And the blocks are very hard and last for many, many laps. Our block has thousands of laps on it---still standard size and we have changed pistons four times. We think the iron block can go to about 400" with a reasonable rod length and still run good RPMs.
Since these are purpose built engies, they have no provision for wet sump oiling-----DRY SUMP ONLY!
About out of breath----need coffee!
In NASCAR, there are three touring series; Cup, Busch and Truck.
The rules are different for each class. The Cup engines are FLAT TAPPET ONLY. That is where the extreme rocker ratios come from(to to 2.1 to 1). On a flat tappet cam, you can use a high ratio rocker and get better area under the lift curve. Also, with flat tappet cams, you use lower pressure springs----the high ratio rockers will last, at least for one race and that is all an engine builder cares about. After the race is over, the rockers go in the trash.
The truck and Busch engines both use roller cams with high spring pressures. You don't see rocker ratios higher than 1.80 to 1. But, the heads and cams are different for the two classes. Busch uses a 390 CFM Holley type carb, thus the cams are smaller and oftentimes the heads are too. The truck engines use 830CFM Holley type carbs and oftentimes the heads are bigger too.
I mention the Holley TYPE carbs because many are not Holley carbs but Titanium billet "lookalikes". They weigh less than two pounds and cost bigs $$$. That is the reason you never see any on the used market and the few you see are dyno carbs. That may change since NASCAR is converting to injection but none of the big $$$ carbs are on the market yet.
Now, lets talk about general cylinder head rules----NASCAR specs valve size(not stem size), valve angles, intake port centerline specs and intake port square inch areas. Most NASCAR engine builders machine away any excess aluminum(weight) around the intake runners---since the size of the runner is spec'd. Therefore for drag racing, there may not be a lot of excess "meat" available around the intake runners. You see a lot of heads with smaller MM size valve stems----these are generally one race valves. Guess what happens to the valves after the race-----trash can! Same with springs, sometimes retainers, titanium shoulder locks, etc. One note----the springs take a specific retainer and titanium shoulder lock. You get into trouble if you don't match the spring to the retainer and the lock.
Now about the cast iron blocks, They are 9.00" deck blocks, same a SB GMs. And, the blocks are big bore(up to 4.185") but short stroke, around 3.25". The main bearing saddles are for a 2.25" Ford type bearing. Only the Elliot aluminum blocks are for a larger 2.50" main bearing. You can easily get a longer stroke crank---all you do is buy a custom billet crank---up to about 3.625" for a 9" deck iron block. And you can bore the blocks larger---but where do you find the deck plates? And the blocks are very hard and last for many, many laps. Our block has thousands of laps on it---still standard size and we have changed pistons four times. We think the iron block can go to about 400" with a reasonable rod length and still run good RPMs.
Since these are purpose built engies, they have no provision for wet sump oiling-----DRY SUMP ONLY!
About out of breath----need coffee!
Posted By: Oyvind Mopar
Re: How good are the P7 engines for drag racing? - 04/21/12 07:52 AM
Thank you, 40Ford for your effort to give some more background to these engines. It is really hard to dig up information about them. One thing I do not understand, what would be different from say a truck engine to a drag engine? I just wonder, because these engines make some 800+ hp on small cubes, and are sort of peaky. If opening the ports I would suspect they get even more peaky, and I would believe they could need more midrange power for launch? (Or a tiny converter?) Are there any other drag engines around at the same cubic inch that gives more power? (Except the high$ P5) I would think they could be ran as they are, "maybe" with more carb, cam and compression and a drivetrain to fit?
What I do know is that decamming them make for a much broader powerband, but cuts some top end power, but still way above in torque and power compared to other similar cube engines
What I do know is that decamming them make for a much broader powerband, but cuts some top end power, but still way above in torque and power compared to other similar cube engines
Posted By: LA360
Re: How good are the P7 engines for drag racing? - 04/21/12 02:21 PM
I would be interested to see what one of these titanium carbs looks like, I am sure I am not alone on that one.
I am curious as to how much the flat tappet engines heads are different to the craftsman truck heads. I have a set of Arrington heads sitting in the garage, their sister heads made 846hp with a low 260's @ 0.050" roller. Haven't bothered putting them onto a flow bench as I don't have valves for them.
I am curious as to how much the flat tappet engines heads are different to the craftsman truck heads. I have a set of Arrington heads sitting in the garage, their sister heads made 846hp with a low 260's @ 0.050" roller. Haven't bothered putting them onto a flow bench as I don't have valves for them.
Posted By: 40ford
Re: How good are the P7 engines for drag racing? - 04/21/12 11:18 PM
From two feet away, a titanium carb looks just like the standard Holley. And, NASCAR uses air gauges to check each carb at the track---so dimensionally they are probably the same as a Holley. The difference is weight.
I never knew there was such a thing until about 5 years ago. Here is the story. We were racing dirt super late models then. After Tony Stewart bought Eldora Speedway, the Nascar stars began running the "Prelude to the Dream" race program. The Nascar stars actually borrowed the late models to run. Our former crew chief was the crew chief for Bill Elliot for that race. Bill flipped his car down the straight and the carb was destroyed. On the return trip, they stopped at our shop and our former crew chief shouted at my son and tossed the carb to him. Expecting to catch a six pound carb---he was amazed it weighed less the two pounds. That's when we learned about the carbs.
How much is a lower center of gravity of four pounds worth?
I never knew there was such a thing until about 5 years ago. Here is the story. We were racing dirt super late models then. After Tony Stewart bought Eldora Speedway, the Nascar stars began running the "Prelude to the Dream" race program. The Nascar stars actually borrowed the late models to run. Our former crew chief was the crew chief for Bill Elliot for that race. Bill flipped his car down the straight and the carb was destroyed. On the return trip, they stopped at our shop and our former crew chief shouted at my son and tossed the carb to him. Expecting to catch a six pound carb---he was amazed it weighed less the two pounds. That's when we learned about the carbs.
How much is a lower center of gravity of four pounds worth?
Posted By: LA360
Re: How good are the P7 engines for drag racing? - 04/21/12 11:34 PM
Moreso justcurious as to how they machined etc. what step over etc, just being a geeky machinist, lol
Posted By: 23T Hemmee
Re: How good are the P7 engines for drag racing? - 04/22/12 03:21 PM
Quote:After seeing what they machined off of the outside of your intake runners to lose weight, it obviously is worth a bunch.....
How much is a lower center of gravity of four pounds worth?
Posted By: coletrickle
Re: How good are the P7 engines for drag racing? - 04/23/12 01:55 AM
Two questions,can anybody tell me what kind of power does one of these motors make with a non NASCAR carb say a 950 or a domintor etc on a as purchased NASCAR or truck engine?And what type of manual transmission would be required for a reliable true street style of car no removable trans tunnel or air shift allowed. Thanks in advance Cole
Posted By: produster
Re: How good are the P7 engines for drag racing? - 04/23/12 02:33 AM
Not sure what one would do with a bigger better carb.
but NASCAR runs a Jericho, but you can contact a bell housing company to make a custom one.
but NASCAR runs a Jericho, but you can contact a bell housing company to make a custom one.
Posted By: DemonDust
Re: How good are the P7 engines for drag racing? - 04/23/12 08:18 AM
Quote:
Two questions,can anybody tell me what kind of power does one of these motors make with a non NASCAR carb say a 950 or a domintor etc on a as purchased NASCAR or truck engine?And what type of manual transmission would be required for a reliable true street style of car no removable trans tunnel or air shift allowed. Thanks in advance Cole
I ran a 18 spline 833 behind mine for a while, I was having problems shifting it over 9000 rpms. I didn't feel like dumping a ton of cash trying to get it to work so I just went auto. It was a blast to drive on the street though
Posted By: Georg
Re: How good are the P7 engines for drag racing? - 04/26/12 07:41 AM
Quote:
Two questions,can anybody tell me what kind of power does one of these motors make with a non NASCAR carb say a 950 or a domintor etc on a as purchased NASCAR or truck engine?And what type of manual transmission would be required for a reliable true street style of car no removable trans tunnel or air shift allowed. Thanks in advance Cole
Rick dynoed my motor with 850cfm Race Demon carb and it showed 845 hp with lower octane race fuel. I belive around 1000cfm carb and higher octane race fuel it probably hit 860..870hp range