Moparts
realistic et goal for a 78 400
Posted By: MPerry
realistic et goal for a 78 400 - 01/10/13 11:33 PM
Yeah I'm bored so just kicking around the idea.
I have a 1978 400 short block out of a Cordoba. I have a few choices on heads(452,346,902,or 516.I would have to buy a cam&lifters unless I swiped the .528 out of my 413.
The car weighs @ 3700lbs 3.91 gears and 3500 stall convertor 28" tires.
What et/mph would you think this could produce? cam suggestions welcome.
I would like it to run at least 12.50 index for the heads up class
Posted By: MPerry
Re: realistic et goal for a 78 400 - 01/11/13 12:33 AM
Well judging by the views and lack of comments its probably unrealistic.
Posted By: GTX MATT
Re: realistic et goal for a 78 400 - 01/11/13 12:39 AM
I don't think its unrealistic, the rest of the car is set up right. I'm not sure the .528 will get you there easily, but it should get you there. It may take a big of tuning. Its a good cam, but not a big top end screamer type. It'll be a nice street/strip setup though. A 509 would probably get you there a little easier, but I'd try the .528 since you have it. 12.50s is probably what I would expect from that. You should certainly be in the 12s, it really just depends on how sharp you tune it and how tired the 400 is.
EDIT I see you don't have a cam. I'd run a DC509 (old one with 108 LSA, in at 102 or 104 ICL), run either the 452s or the 516s. I'd run the 452s, have them milled as much as you can. If you want give them a shot at home porting. I think it'll run strong though, the car is set up well with that converter and gearing.
Posted By: MPerry
Re: realistic et goal for a 78 400 - 01/11/13 12:42 AM
I think I have a .509 sitting in the 400 right now. I had it briefly in my 413.
The 452 are milled already.
Posted By: Mopar-Al
Re: realistic et goal for a 78 400 - 01/11/13 12:42 AM
Seems like even with low comp, You should be able to squeeze 400 hp out of it with some good machine work. That may get you into the low 12 to mid 12's
Posted By: MPerry
Re: realistic et goal for a 78 400 - 01/11/13 12:52 AM
would a 2x4 tunnel ram hurt or help?
Posted By: earthmover
Re: realistic et goal for a 78 400 - 01/11/13 12:59 AM
i have a 75 400 that I am doing the same to right now...most tell me its not going to do this or that.. compression to low.. I took a measurement and came up with the piston being in the hole 37th.total.. I have a old crane cam hyd. I think its 504/528 something along that line with a 112 plan to install it at 106 or so..i have a tm6 intake and a 750dbl pumper carb..will run a 727 with a 28/3000 verta and 456 gear for right now 70 duster frame conn. ss spring,mini tubbed, oh yea I plan to put some nos on it as well.. this will be my street car/toy until I finish my chassis car...hope it will be in the 7xx in the 1/8 mile but who knows...
Posted By: HYPER8oSoNic
Re: realistic et goal for a 78 400 - 01/11/13 01:46 AM
Quote:
Seems like even with low comp, You should be able to squeeze 400 hp out of it with some good machine work. That may get you into the low 12 to mid 12's
12.50 et or less is real. 400-425 hp is about right. 452's are a little easier to work with to gain power (bigger valves, some pocket work). since you have them milled, you may go up in the comp ratio, but not by much. Excellent point from the other members is to get a cam, matched to your specs and advance in the intake centerline a bit more to raise cylinder pressure. Check piston /valve clearances though. However, work the chassis to transfer the weight better and to HOOK
WELL. Basic stuff - front end rise/alignment, frame rigidity, solid crossmembers and sub-connectors and by all means proper rear shock travel. You can have power, but without a solid foundation to transfer it from the frame thru the rear wheels and, finally to the ground - it's pointless!! Food for thought. 
By the way, do you have a TQ or a Holley sitting up top?
Posted By: MPerry
Re: realistic et goal for a 78 400 - 01/11/13 01:50 AM
I have a bunch of different carbs to choose from. The 413 has an 850dp on it. I have a few other holleys,a few TQs,an edelbrock,and a couple quadrajets.
Posted By: HYPER8oSoNic
Re: realistic et goal for a 78 400 - 01/11/13 01:59 AM
Either the 850 (jetted/w proper squirters),
the 800 TQ (tuned, w/adjusted secy air door), or even a performance tuned 750 EDDY will
do the job.
Posted By: Mr.Yuck
Re: realistic et goal for a 78 400 - 01/11/13 02:28 AM
not going to get there with that combo. Maybe 13.50 for 12's you are going to need more compression, some head work... can you use the 413?
Posted By: MPerry
Re: realistic et goal for a 78 400 - 01/11/13 02:32 AM
Yes that is what was in the car. I'm just afraid it will be too fast for 12.50 index once it hooks.
Posted By: Mr.Yuck
Re: realistic et goal for a 78 400 - 01/11/13 02:40 AM
I think with the 413 you're going to be close to 12.50. The 528 is a nice mello cam. Depending on what else you have. I'm guessing you have headers, a decent intake and electronic ignition. If so leave the 413 in. Even with the 509 in the 413 I don't see a problem. If you ran the 509 with ported heads, good headers (1 7/8+) and 4.10's it MIGHT run 12.20.
Posted By: MPerry
Re: realistic et goal for a 78 400 - 01/11/13 02:44 AM
headers,holley street dominator,electronic distributor locked out and set for 38 degrees total
Posted By: dOc …
Re: realistic et goal for a 78 400 - 01/11/13 02:56 AM
....waaaay mo-compression ...
Posted By: WO23Coronet
Re: realistic et goal for a 78 400 - 01/11/13 03:37 AM
Not sure if you've seen this post but your setup sounds pretty similar to what this is:L
https://board.moparts.org/ubbthreads/show...e=1#Post7538803Your goals seem doable
Posted By: 493_DART
Re: realistic et goal for a 78 400 - 01/11/13 07:32 AM
Classic Moparts thread..........
with the parts listed and factory heads....
at 3700 lb .....high 12's.
at 3300 with the out -dated 509 / out dated iron heads / 3:91/410 gear / slicks/ etc... you can get to 12.20
Posted By: MPerry
Re: realistic et goal for a 78 400 - 01/11/13 11:55 AM
Ok thanks for the input. I'm going to leave the 413 as is for now.
I'll try putting the 400 together with the 509 cam just to see how it performs.
Posted By: quickd100
Re: realistic et goal for a 78 400 - 01/11/13 12:00 PM
I milled a set of 452's .100 and turned them into closed chamber heads. How long will they last without cracking?....flip a coin I had a set of 516's that I milled extensively and they took 12 years to crack.Dave
Posted By: MPerry
Re: realistic et goal for a 78 400 - 01/11/13 12:13 PM
My 452's are on the 413 so I'll probably try the 516's.
Its either 902's(1974 440) 346(1972 400) or the 516's 1963 413)
Posted By: Mr.Yuck
Re: realistic et goal for a 78 400 - 01/11/13 02:06 PM
I'd probably leave it alone and tune on it. I found that my old 440 w/ the 528 liked a tighter lash. I went form the factory .028/.030 down to .024/.026 and it seemed to pull longer. The 850 is probably your best bet for a carb.
The 516 probably don't flow as well, but they do give you more compression. If you do use the other heads at least do a gasket match home porting job before you drop them on.
I'd think the 413 w/ some tuning would be at the 12.50 mark. The 509 would do it easier. But the 509 in the stock 400 would be a total dog.
Posted By: buck440
Re: realistic et goal for a 78 400 - 01/11/13 03:34 PM
not a 400 but my bone stock bottom end 77 motor home 440 went 11.94 @114. in my 3650 lb duster thats with me in it. with nothing more than a 509,915 heads milled .060 no port work stockvalve size. torker intake 850 speed demon carb 3000 stall 4.56 gear.
Posted By: gregsdart
Re: realistic et goal for a 78 400 - 01/11/13 03:54 PM
I am assuming you are going to rebuild the shortblock with an over bore? Like the post on the 400 motor and MP cams shows, the more cam you put in it, the faster it will go. The limit is about the 590 cam. The 850 is a good choice for carb. Good machine work, file fit rings, as much compression as you can put in it, and 1 7/8 headers will all help. A solid lifter cam will allow more rpm giving more hp. One key is cylinder head prep. Bowl work and 2.14/ 1.81 valves will do a lot for the build. A good single plane manifold to match a 557 or 590 cam, and if you don't run high elevens something isn't right. This basic recipe put a 383 roadrunner into the low 12.0s at 3850 with a 268 @ .050 hydraulic 540 lift cam (stock stamped rockers!)that quit at 5600/6000 rpm due to valve float issues. You would have more cubes and a better cam if you go 557 or 590, and the ability to ring more hp out of it with more rpm.
Posted By: Twostick
Re: realistic et goal for a 78 400 - 01/11/13 05:17 PM
You mentioned a tunnel ram. Run it if you got it.
Are any of your cylinder head choices "ready to run" ie milled, bigger valves etc? 516's will help with compression but if they need any work you might be better off shopping for a set of used Stealths or RPM's. You can pretty much guarantee 47 yr old heads are going to need valves and guides at the very least plus the machine work and valve job so you are right there money wise.
Kevin
Posted By: MPerry
Re: realistic et goal for a 78 400 - 01/11/13 05:35 PM
Tunnel ram is for a low deck so it won't work for the 413. I have more time than money at the moment.
I know the 413 runs well so I will leave it be.
Posted By: Dean_Kuzluzski
Re: realistic et goal for a 78 400 - 01/11/13 11:02 PM
Quote:
Tunnel ram is for a low deck .........
I have more time than money at the moment.
Hey Mike! 
More time than money spells buy/borrow a die grinder and template/bowl port the 516's, mill and get guides/seats done.
I gained 3 mph through the traps when I ported my 516's. Well worth the time.
Great thread. Glad to see there's some of us old schoolers out there that are just trying to have some fun on a budget. 
Posted By: MPerry
Re: realistic et goal for a 78 400 - 01/11/13 11:26 PM
Quote:
More time than money spells buy/borrow a die grinder and template/bowl port the 516's, mill and get guides/seats done.
I gained 3 mph through the traps when I ported my 516's. Well worth the time.
Great thread. Glad to see there's some of us old schoolers out there that are just trying to have some fun on a budget.
I have a nice die grinder where would I find the templates?
Posted By: HYPER8oSoNic
Re: realistic et goal for a 78 400 - 01/12/13 04:02 AM
Quote:
not going to get there with that combo. Maybe 13.50 for 12's you are going to need more compression, some head work... can you use the 413?
Hold up a sec, Mr. Y. 
You are forgetting he has an alternative to the longer arm of the 413. RPM potential!! He can spin it a bit less than a 383 to make power, (and a bit more than a 413) but overall make slightly better times than you posted. Mopar Muscle did a couple of builds on the 400 Mopar with very impressive results. Sure, the car could use a bit more gear, (4.10/4.30, cam depending) but for what he has already, he's almost there! The real power is in the cam and ignition timing and carb tuning. Not as easy as the 413, but you WILL be surprised when it's right!! Have to get carb/ignition spot-on for the combo to really fly!! Concerning the porting templates, Mancini or any major Chrysler Dealer sells them, the part number is P4120437, pretty reasonable.
Posted By: moparmanjames
Re: realistic et goal for a 78 400 - 01/12/13 04:55 AM
Quote:
The real power is in the cam and ignition timing and carb tuning.
The real power is in the whole combination, but it's been my experience that a good set of heads is #1 in the combination.
Posted By: moparmanjames
Re: realistic et goal for a 78 400 - 01/12/13 05:05 AM
Quote:
Classic Moparts thread..........
with the parts listed and factory heads....
at 3700 lb .....high 12's.
at 3300 with the out -dated 509 / out dated iron heads / 3:91/410 gear / slicks/ etc... you can get to 12.20
I went 12.50's @ 110 in my 3700lb Roadrunner with 3.23 gears.
I built a 440 with home ported 516 heads, 10:1 compression, 509 cam, solid 7 blade fan with stock accessories and a 3500 stall/727 on MT Sportsman pro's driving it to the track here in Las Vegas.
Posted By: Twostick
Re: realistic et goal for a 78 400 - 01/12/13 07:12 AM
Quote:
Tunnel ram is for a low deck so it won't work for the 413. I have more time than money at the moment.
I know the 413 runs well so I will leave it be.
I thought we were talking about a 400.
Kevin
Posted By: MPerry
Re: realistic et goal for a 78 400 - 01/12/13 09:01 AM
Quote:
I thought we were talking about a 400.
Kevin
Yes the 400 is the intended subject. I would be able to use the tunnel ram on that. There was doubt about the 400 being capable of achieving the goal. That is how the 413 got mixed in the subject.
Posted By: HYPER8oSoNic
Re: realistic et goal for a 78 400 - 01/12/13 06:45 PM
Quote:
Quote:
The real power is in the cam and ignition timing and carb tuning.
The real power is in the whole combination, but it's been my experience that a good set of heads is #1 in the combination.
Obviously the heads are #1, but they were already
talked about. His chosen combo (cam/carb and ignition timing) has to be set up and fine tuned
(trial and error at the track) for max power. Seems like the poster wants to use what he has for the 400, and to RUN with less cash outlay possible. And YES it can be and HAS been done (since the B motor was built)! Thanks Dean for stating that point!
Posted By: Twostick
Re: realistic et goal for a 78 400 - 01/12/13 07:13 PM
I don't think there is much question whether 400 cubes can do the deed. There's no replacement for displacement but 13 cubes won't make or break you here IMHO.
If you are using the stock short block with pistons .100"ish in the hole, compression will be less than ideal so I would want to use the best head I could lay my hands on. Any of the heads you have can be made to work for you but even the cost of a good rebuild and valve job will at the very least approach the cost of Stealths or Eddies so I would try and get a set used and reap the benefits of an aluminum head for very little additional cost. Best money you can spend.
Assuming the short block is sound I would try the MP509 you have with a set of RPM's and the tunnel ram and call it a day.
Kevin
Posted By: MPerry
Re: realistic et goal for a 78 400 - 01/12/13 07:18 PM
Well I'm going to give it a shot & find out. 12.50 or bust!
I will be able to bracket race it either way.
Posted By: HYPER8oSoNic
Re: realistic et goal for a 78 400 - 01/14/13 02:05 AM
Takes a little bit of tuning work (on your part), but you'll hit the mark for sure.
You'll have fun testing and tuning. Just remember to keep
a SOLID baseline (reference point) BEFORE you tune!!
Posted By: earthmover
Re: realistic et goal for a 78 400 - 01/14/13 03:08 AM
keep us posted ... I will post on my 400 when I get it going...
Posted By: MR_P_BODY
Re: realistic et goal for a 78 400 - 01/14/13 05:22 AM
Quote:
Well I'm going to give it a shot & find out. 12.50 or bust!
I will be able to bracket race it either way.
do a pocket port on the heads you want to use...
thats real easy to do.... the conv will make a big
difference as well as the chassis set up... if your
looking to go 12.50 in the heat you need to make it
run 12.30 in good air and I'm sure some of these guys
are telling you the best they ran... you need more
gear but use what you have... the 509 might get close
with the porting... also do a match port to the
intake and heads... with your die grinder knock out
any chunks in the runners and just smooth up the
short turn on the heads... if you can have the heads
milled some to clean them and make them flat will
help... get the front of the car as loose as possible
so it lifts and get some rancho 9000 shocks for the
rear and I think you'll get there.... use your 850
carb
Posted By: gregsdart
Re: realistic et goal for a 78 400 - 01/14/13 04:14 PM
Quote:
Well I'm going to give it a shot & find out. 12.50 or bust!
I will be able to bracket race it either way.
I am not sure how well they will fit, but QUICKD100 had great success with a pair of Thermoquads on a Tunnelram Hemi. Might be a cheap alternative, and once dialed in, ought to run like scat!!! I am betting two tenths quicker than the best single plane deal.
What I like about this combo is the small preimarys for cruise, and vacuum secondary's providing as much air as the combo will need for max power.
As far as mounting, there is a way. Might need to get creative, but it can be done. I think I have two TQ to holley pattern adapters, and if you choose to try this combo, they are yours for the shipping.
A couple of swap meet carbs, two rebuild kits and some jets and you are in business.
Posted By: MPerry
Re: realistic et goal for a 78 400 - 01/14/13 04:17 PM
Quote:
you need more
gear but use what you have...
I have another 3rd member with 4.30's on a strange spool if you think that is better.
Posted By: MR_P_BODY
Re: realistic et goal for a 78 400 - 01/14/13 04:35 PM
Quote:
Quote:
you need more
gear but use what you have...
I have another 3rd member with 4.30's on a strange spool if you think that is better.
Set your gear ratio and tire size to determine your
trap rpm and set the conv to get your 60'(make sure
you figure the conv slippage in with the trap rpm)
Posted By: MPerry
Re: realistic et goal for a 78 400 - 01/14/13 04:42 PM
Quote:
(make sure
you figure the conv slippage in with the trap rpm)
You just lost me! 
Posted By: MPerry
Re: realistic et goal for a 78 400 - 01/14/13 04:51 PM
Car originally had 26" tires a 4.30 gear lines up to 7000rpm at 125mph
3.91's with 26" 7000 at 133mph
28" 4.30 7000 at 135
28" 3.91 7000 at 150
Posted By: MR_P_BODY
Re: realistic et goal for a 78 400 - 01/14/13 04:59 PM
Quote:
Quote:
(make sure
you figure the conv slippage in with the trap rpm)
You just lost me!
Just for a number lets say the conv has 10% slippage
you need to figure that 10% into the trap rpm if
you want a real trap rpm
Posted By: MPerry
Re: realistic et goal for a 78 400 - 01/14/13 05:03 PM
how does one figure out converter slippage?
Posted By: MPerry
Re: realistic et goal for a 78 400 - 01/14/13 06:12 PM
Quote:
[
I am not sure how well they will fit, but QUICKD100 had great success with a pair of Thermoquads on a Tunnelram Hemi. Might be a cheap alternative, and once dialed in, ought to run like scat!!! I am betting two tenths quicker than the best single plane deal.
What I like about this combo is the small preimarys for cruise, and vacuum secondary's providing as much air as the combo will need for max power.
As far as mounting, there is a way. Might need to get creative, but it can be done. I think I have two TQ to holley pattern adapters, and if you choose to try this combo, they are yours for the shipping.
A couple of swap meet carbs, two rebuild kits and some jets and you are in business.
I like that idea. I have a pair of TQ's and it seems like a cheap and cool plan.
Posted By: MPerry
Re: realistic et goal for a 78 400 - 01/14/13 08:18 PM
The tunnel ram.
Posted By: moparmanjames
Re: realistic et goal for a 78 400 - 01/14/13 11:21 PM
Quote:
Quote:
Well I'm going to give it a shot & find out. 12.50 or bust!
I will be able to bracket race it either way.
do a pocket port on the heads you want to use...
thats real easy to do.... the conv will make a big
difference as well as the chassis set up... if your
looking to go 12.50 in the heat you need to make it
run 12.30 in good air and I'm sure some of these guys
are telling you the best they ran... you need more
gear but use what you have... the 509 might get close
with the porting... also do a match port to the
intake and heads... with your die grinder knock out
any chunks in the runners and just smooth up the
short turn on the heads... if you can have the heads
milled some to clean them and make them flat will
help... get the front of the car as loose as possible
so it lifts and get some rancho 9000 shocks for the
rear and I think you'll get there.... use your 850
carb
Good advice but make sure you use the 516's so you raise compression with the closed chamber heads. Use at least a 2.14 if not a 2.19 intake valve and open up the pocket accordingly.
Like he said just clean and polish the short side radius but try and open up the area a little on both sides of the valve guide boss.
Use those 4.30 gears and that thing should run great with the tunnel ram.
Posted By: NTOLERANCE
Re: realistic et goal for a 78 400 - 01/15/13 12:14 AM
Quote:
Quote:
Well I'm going to give it a shot & find out. 12.50 or bust!
I will be able to bracket race it either way.
I am not sure how well they will fit, but QUICKD100 had great success with a pair of Thermoquads on a Tunnelram Hemi. Might be a cheap alternative, and once dialed in, ought to run like scat!!! I am betting two tenths quicker than the best single plane deal.
What I like about this combo is the small preimarys for cruise, and vacuum secondary's providing as much air as the combo will need for max power.
As far as mounting, there is a way. Might need to get creative, but it can be done. I think I have two TQ to holley pattern adapters, and if you choose to try this combo, they are yours for the shipping.
A couple of swap meet carbs, two rebuild kits and some jets and you are in business.
Thats exactly what I am looking to do. I do have a pair of 450 holleys on my T-ram now, but would like to try the T-quad for the above mentioned reasons and the sheer wow factor.
How critical do you think it would be to have the same numbered carbs? SO long as the CFM is the same....or get the same numbers?
Sorry for the hijack.
Posted By: MPerry
Re: realistic et goal for a 78 400 - 01/15/13 12:30 AM
I don't think it will matter much as long as the carbs are close. I know I'm not going to worry too much about it.
Posted By: JohnRR
Re: realistic et goal for a 78 400 - 01/15/13 03:36 PM
Mike you could get a set of spacers and use that tunnel ram on the 413.
Posted By: MPerry
Re: realistic et goal for a 78 400 - 01/15/13 03:42 PM
I never thought of that. Who makes spacers?
Posted By: MPerry
Re: realistic et goal for a 78 400 - 01/15/13 03:50 PM
Never mind after a little searching I found some. Unfortunately I don't see them being cost effective at over $150 with shipping.
Posted By: 72blubird
Re: realistic et goal for a 78 400 - 01/15/13 06:42 PM
Seems over double what you should be able to get a simple spacers for. If you want them search a little harder should be able to get spacers shipped for under $75
Posted By: MPerry
Re: realistic et goal for a 78 400 - 01/15/13 08:33 PM
I'll keep my eyes open. I'm going to keep the 413 as it is and work with the 400 for now. I'll post some progress once I'm am able to escape this dungeon in a few days.