Here we go again; More cam questions
#687284
05/03/10 12:10 PM
05/03/10 12:10 PM
|
Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
Scott Carl
OP
pro stock
|
OP
pro stock
Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
|
I thought I had this resolved in my mind until I read the article on AllPar.com about performance upgrades for the 318.  They claim that anything more than a .430-.455 lift will kill low end power. Here's my delema. I'm currently running 2.76 gears behind a 904. My 318 will have a 600 cfm Carter AVS on a stock cast iron intake. I was going to go with Cam #1, but was told I will require at least 3.31 gears and better with 3.55 to make it work. Given the claim of the allpar article, would I be better off with something like Cam #2? Could I maintain my 2.76 gears with this cam? The car (sig photo; '74 Challenger) will mainly be driven on the street on week-ends through the local Sonic and such, but I'd also like to take a road trip or two without breaking the bank at the gas pumps on the way. Will the bigger cam with the lower gears really kill my mileage? Or am I splitting hairs on these to cams? I want to maintain decent low-end power but I don't want 3rd gear wound up so tight that I can watch the gas gauge fall as I drive on the interstate.  Specs: Cam #1 CCA-K20-223-3 Basic Operating RPM Range: 1,600-5,800 Duration at 050 inch Lift: 224 int./230 exh. Advertised Duration: 268 int./280 exh. Valve Lift with Factory Rocker Arm Ratio: 0.477 int./0.480 exh. lift Lobe Separation (degrees): 110 Cam #2 CCA-K20-221-3 Basic Operating RPM Range: 1,000-5,200 Duration at 050 inch Lift: 212 int./218 exh. Advertised Duration 256: int./268 exh. Valve Lift with Factory Rocker Arm Ratio: 0.447 int./0.455 exh. lift Lobe Separation (degrees): 110 I know the mileage will suffer a bit due to the upgrades anyway and there are a lot of factors I haven't included here, but I'm just trying to get some informed opinions. Thanks for taking the time. Scott 
|
|
|
Re: Here we go again; More cam questions
[Re: Scott Carl]
#687285
05/03/10 02:44 PM
05/03/10 02:44 PM
|
Joined: Jun 2006
Posts: 5,163
CT
GTX MATT
master
|
master
Joined: Jun 2006
Posts: 5,163
CT
|
Well whoever wrote the article on Allpar doesnt know much because you can not judge much about a cam based on lift. Duration is what determines the powerband. Smaller duration cams usually have less lift but not always, especially with todays agressive ramps and roller cams.
There will definately be a difference. In my opinion the XE268 is too much for you with 2.76s. What is the rest of the combo for this 318 (intake, compression, heads, headers or manifolds). You will definately need a higher stall converter for it in that 318 and it will have a noticeable idle.
The XE256 is more similar to a 340 cam and would be a better choice for you assuming this is just a stock 318 with an aftermarket intake and 4 barrel. I would still step up to 3.55s either way. 3.23s are a nice highway gear. 2.76s really dog a car down though.
You can also kill around town mileage with such a high gear in the rear end like 2.76s because you have to use more power from the engine to get the car rolling, go up hills, etc. If you dont believe it look at the 80s Diplomats and Fifth Avenues, they had like 2.55s and got 10 mpg with a 318.
Last edited by GTX MATT; 05/03/10 02:48 PM.
Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street
|
|
|
Re: Here we go again; More cam questions
[Re: GTX MATT]
#687286
05/03/10 03:48 PM
05/03/10 03:48 PM
|
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
|
I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
|
as GTX matt said, it's .050 duration you need to look at, not lift. and FWIW, most dips/5ths have 2.24 gears and 27" tires. my stock 5th's got ~13.5 in town, 22-25 on the highway. for the 2.76 rears (I'd keep them if you plan on any freeway driving), I'd look at a comp XE250 lunati voodoo 60400, an XE256 or voodoo 60401 at the biggest. a higher than stock stall converter will also wake up the car even with these tall gears, and make them more livable, as you'll be into the meat of your powerband at max stall. something like a stock high stall (will probably flash to 2000 RPM) or upwards of a 166-175K converter (will probably flash to 2300-2700) would wake it up. if it were me, I'd go the voodoo 60400, & comp 901 springs. if you are thinking of a head swap, a set hughes iron rams and some used magnum rockers will probably add a good 50-75HP over some stock 318 heads with the above cams
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
|
|
|
Re: Here we go again; More cam questions
[Re: GTX MATT]
#687288
05/03/10 06:19 PM
05/03/10 06:19 PM
|
Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
Scott Carl
OP
pro stock
|
OP
pro stock
Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
|
Thanks guys. This gives me food for thought. It also presents a couple more questions.  Quote:
What is the rest of the combo for this 318 (intake, compression, heads, headers or manifolds). You will definately need a higher stall converter for it in that 318 and it will have a noticeable idle.
This is virtually a stock 150 hp 318 and due to a limited buget, I am gonna have to keep it that way except for the cam. Probably gonna go through the engine so I have that expense to look forward to as well. different heads, headers etc are not in the buget at this time. The carb, intake and exhaust were given to me. The carb is a MO 4966S off a '71 BB C-body (600 cfm?) The intake is from a '66 273, and the exhaust are 318 magnum. Unsure what vintage, but I think '91 or '92. Haven't researched muffs yet but probably Thrush type turbos with 2 1/2 pipe.
Quote:
In my opinion the XE268 is too much for you with 2.76s
I'd look at a comp XE250 lunati voodoo 60400, an XE256
I recognize the numbers from the Summit specs as grind numbers. Are they the standard for the industry? Would Lunati's XE250 be the same as Comp's XE250 etc? The reason I ask is that I like the covenience and prices of the full kits; cam, lifters, springs etc. and Comp seems to be the only ones that offer full kits. Anyone else have these online? I priced the kit at my local O'reilly's an it was over $100 more.
Quote:
something like a stock high stall (will probably flash to 2000 RPM) or upwards of a 166-175K converter (will probably flash to 2300-2700) would wake it up.
So what would be the stall figure for a stock 904? And what is flash? I understand higher stall TCs affect the low end but do they have any affect on highway driving? Thats all I can think of right now. I'm sure there is more I should be asking but not sure what at this point. 
|
|
|
Re: Here we go again; More cam questions
[Re: Scott Carl]
#687289
05/03/10 08:53 PM
05/03/10 08:53 PM
|
Joined: Jun 2006
Posts: 5,163
CT
GTX MATT
master
|
master
Joined: Jun 2006
Posts: 5,163
CT
|
No but the cams you listed are both in Comp's line of Xtreme Energy cams and those are their grind numbers. Lunati and Comp wont use the same part number, it is not an industry standard.
The flash speed of the converter the rpm that it will allow the engine to instantly rev to if you floor it from a dead stop.
A higher stall converter can effect highway driving if the stall speed is below the rpm that you are travelling.
Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street
|
|
|
Re: Here we go again; More cam questions
[Re: Scott Carl]
#687291
05/04/10 10:33 AM
05/04/10 10:33 AM
|
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
|
I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
|
Quote:
Thanks guys. This gives me food for thought. It also presents a couple more questions.
Quote:
What is the rest of the combo for this 318 (intake, compression, heads, headers or manifolds). You will definately need a higher stall converter for it in that 318 and it will have a noticeable idle.
This is virtually a stock 150 hp 318 and due to a limited buget, I am gonna have to keep it that way except for the cam. Probably gonna go through the engine so I have that expense to look forward to as well. different heads, headers etc are not in the buget at this time. The carb, intake and exhaust were given to me. The carb is a MO 4966S off a '71 BB C-body (600 cfm?) The intake is from a '66 273, and the exhaust are 318 magnum. Unsure what vintage, but I think '91 or '92. Haven't researched muffs yet but probably Thrush type turbos with 2 1/2 pipe.
Quote:
In my opinion the XE268 is too much for you with 2.76s
I'd look at a comp XE250 lunati voodoo 60400, an XE256
I recognize the numbers from the Summit specs as grind numbers. Are they the standard for the industry? Would Lunati's XE250 be the same as Comp's XE250 etc? The reason I ask is that I like the covenience and prices of the full kits; cam, lifters, springs etc. and Comp seems to be the only ones that offer full kits. Anyone else have these online? I priced the kit at my local O'reilly's an it was over $100 more.
Quote:
something like a stock high stall (will probably flash to 2000 RPM) or upwards of a 166-175K converter (will probably flash to 2300-2700) would wake it up.
So what would be the stall figure for a stock 904? And what is flash? I understand higher stall TCs affect the low end but do they have any affect on highway driving? Thats all I can think of right now. I'm sure there is more I should be asking but not sure what at this point.
stall RPM is the RPM the converter multiplies the torque the most at. flash RPM is what the converter jumps to when you hit the gas. in my experience, it is usually a little higher than the actual stall speed.
a stock low stall 904 will probably have a stall speed in the 1400 RPM and maybe flash to 1500-1600.
XE250/256 are comp's grind numbers, not an industry standard. the comp XE line uses their most aggressive .842" diameter lifter lobes. the lunati voodoo for chryslers actually use a lobe designed for a .904" lifter, so they get a little more lift/.050 duration for a given seat duration.
if you're not planning on headers, keeping the 2.76's and the low stall converter, and using that 273 intake (I'd personally look for a stock 360 intake or an eddie performer, which you can usually find used for under $100), I'd probably get the voodoo 60400 cam, and comp #901 springs.
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
|
|
|
Re: Here we go again; More cam questions
[Re: Scott Carl]
#687292
05/04/10 12:29 PM
05/04/10 12:29 PM
|
Joined: Oct 2009
Posts: 266
Seattle Wa
PowerWagonDude
enthusiast
|
enthusiast
Joined: Oct 2009
Posts: 266
Seattle Wa
|
To keep good mileage and highway driveability, I would personally go with 3.23 rear gears. If you have an 8 3/4 they are cheap and easy to swap. Dont bother with the converter at this point. I would use the Mopar Performance cam 260/.430 lift #P4452759 http://www.summitracing.com/parts/DCC-4452759/ or Comp Cams High Energy 260/.440 cl20-210-2 http://www.summitracing.com/parts/CCA-CL20-210-2/ I have also used Summits house brand grinds with success. For comparison your stock 318 cam has 240 duration and .370 lift. A 360 cam has 252 duration and .410 lift. Mopar Performance recommends their 260 grind listed above as the best 318 high performance cam, better than the old 340 cam. 
|
|
|
Re: Here we go again; More cam questions
[Re: PowerWagonDude]
#687293
05/04/10 03:38 PM
05/04/10 03:38 PM
|
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
|
I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
|
also, to compare the important numbers, a stock 318 cam is ~180 degrees @.050, a 360 cam is ~190...
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
|
|
|
Re: Here we go again; More cam questions
[Re: PowerWagonDude]
#687294
05/04/10 04:32 PM
05/04/10 04:32 PM
|
Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
Scott Carl
OP
pro stock
|
OP
pro stock
Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
|
Quote:
To keep good mileage and highway driveability, I would personally go with 3.23 rear gears. If you have an 8 3/4 they are cheap and easy to swap. Dont bother with the converter at this point. I would use the Mopar Performance cam 260/.430 lift #P4452759 http://www.summitracing.com/parts/DCC-4452759/ or Comp Cams High Energy 260/.440 cl20-210-2 http://www.summitracing.com/parts/CCA-CL20-210-2/ I have also used Summits house brand grinds with success. For comparison your stock 318 cam has 240 duration and .370 lift. A 360 cam has 252 duration and .410 lift. Mopar Performance recommends their 260 grind listed above as the best 318 high performance cam, better than the old 340 cam.
The Comp cam above also comes in a full kit with springs, retainers, timing set, etc. For that list price, $311 and change, I'm sure I'd be spending that much or more buying the individual parts anyway. 
BTW, yes I do have the 8 3/4 rear.
|
|
|
Re: Here we go again; More cam questions
[Re: Scott Carl]
#687295
05/04/10 08:51 PM
05/04/10 08:51 PM
|
Joined: Apr 2010
Posts: 1,216
Under My Car
Mopar_Country
pro stock
|
pro stock
Joined: Apr 2010
Posts: 1,216
Under My Car
|
I would recommend comp cam http://www.compperformancegroupstores.co...;Category_Code=This is a good cam for street use. It will work with your stock converter. I put this in my 318 with a 340 spreadbore intake NON egr, thermoquad carb and 1 5/8" tube headers. My 8 3/4 rear got 3.55's and a posi unit added. I'm shooting for 20mpg for normal driving. Should be a good performer as it runs very strong. I am going to cap it off with 2 1/2" exhaust with free flowing mufflers, have not decided on those as of yet. I would also recommend spending a little extra for a true double roller timing chain and gears. There is one in the kit but it just don't get it. The kit will have cam, lifters, springs, retainers, locks and lube. Your stock valve train will be fine for street use and the occasional race. Remember this is the heart of your engine and it is not the place to skimp.
|
|
|
Re: Here we go again; More cam questions
[Re: Mopar_Country]
#687296
05/04/10 09:49 PM
05/04/10 09:49 PM
|
Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
Scott Carl
OP
pro stock
|
OP
pro stock
Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
|
Quote:
I would recommend comp cam http://www.compperformancegroupstores.co...;Category_Code=
This is a good cam for street use. It will work with your stock converter. I put this in my 318 with a 340 spreadbore intake NON egr, thermoquad carb and 1 5/8" tube headers. My 8 3/4 rear got 3.55's and a posi unit added. I'm shooting for 20mpg for normal driving. Should be a good performer as it runs very strong. I am going to cap it off with 2 1/2" exhaust with free flowing mufflers, have not decided on those as of yet. I would also recommend spending a little extra for a true double roller timing chain and gears. There is one in the kit but it just don't get it. The kit will have cam, lifters, springs, retainers, locks and lube. Your stock valve train will be fine for street use and the occasional race. Remember this is the heart of your engine and it is not the place to skimp.
I will be running magnum exhaust manifolds with 2 1/2" pipe. Not as good as headers but it will certainly breathe better than the stock manifolds. I also have to make it tolerable for the missus to drive from time to time 
I've run both types of chains over the years. In Mopars as well as GM stuff. Never really noticed a difference, but the chain was usually changed to replace the stock chain that had jumped or was stretched to where the engine just didn't run well anymore. I've never done any serious racing and probably won't in the future. Like I said in my OP, this will be just a weekender with an occasional trip from Omaha to Topeka, or St. Louis at the furthest. Is there really that much difference in the two types of chains? Interestingly, I remember at least one of the double roller sets I installed, I chose because it was cheaper than the stock non-roller chain
|
|
|
Re: Here we go again; More cam questions
[Re: PowerWagonDude]
#687298
05/05/10 12:56 PM
05/05/10 12:56 PM
|
Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
Scott Carl
OP
pro stock
|
OP
pro stock
Joined: Aug 2008
Posts: 1,568
Omaha, Nebraska
|
Quote:
You can run the stock valve springs with the 260 grind cams listed above or with any of the Summit Racing house brand cam/lifter kits. Timing chain sets are $20-$40. If you are really tight on cash, just use one of Summit Racings cam and lifters with their timing set. I have swapped them and not even bought a new timing cover gasket. Just goop it up. You should be able to do it for less than $200 and scrounge up a 3.23 third member. Good luck 
Given that I have 100k on this engine, wouldn't I benefit from new springs anyway? I am trying to spend as little as possible but I don't want to scrimp in the wrong areas.
I also just got a response from Comp Cams after filling out their recommendation form. They suggest the XE250 with 250/260 Duration and .432/.444 Lift. And there's a 1 year warranty on that kit.  The cam has a operating range from 800 - 4800 rpm. Unless I totally missed the boat, this means my stock converter should work OK. I know I have to do some trans work and will most likely replace the TC then and I think I will try to find a 3.23 gear set. Thanks for all the input. I think I understand a little more about cams now. The first engine I rebuilt myself was in 1976. I ignored all advice and put new lifters in with the old cam. It was a '69 340 and I installed it in a '74 B100 van. Needless to say, it didn't run well for long....
|
|
|
|
|
