Heads or cam

[gexgexgexgex]

I just bought a 94 caprice engine that i plan on putting in to my 240z. My question is would it be better to upgrade the heads to stock alum ones from an f-body or corvette or should i just put in a new cam and keep the iron heads. What i am looking for is HP not torque because the Z is so light i do not need it. would the alum heads bolt on or is there something special about them.

[Mike C]

If you can only do one or the other, do the cam. As anecdotal evidence, I had two friends who had Impala SS. A '94 that they pocket ported the iron heads and put a cam in it and a '96 that had AFR heads and SLP headers. Both cars had 2 1/2" exhaust systems Flowmaster on the '94 and Borla on the '96. The '94 put down 297 whp with the iron exhaust manifolds and the the '96 put down 267 whp. The guy with the '94 spent less than $500 while the '96 owner spent nearly $3000.

[grumpyvette]

what your saying about pocket porting the heads and adding a well choosen cam making more power is basically correct

but ID POINT OUT that theres a un-mentioned FLAW in the thought process most guys reading that will have , and reaching to the wrong conclusion

 

lets say the AFR heads flow potentially at 260cfm and the stock, pocket ported heads flow 235cfm with the valve open to .600 lift

 

for the purpose of making it clearer to see lets pretend the stock valves open to a .420 lift with the stock cam and the aftermarket cam with its increased durration lifts to a .520 lift, the stock pocket ported heads flow more than enought to supply all the flow the .520 lift allows, but the AFR heads are seriously restricted by the stock cam,(and probably by that aftermarket cam) if both cars had a correctly matched cam that allowed thier full flow potential, theres zero question the AFR would pull significantly higher hp, but no matter how well the ports potentially flow, if the valves barely open and the gearing and stall speed rarely allow that flow theres no gains

 

look at this, and keep in mind the edelbrock heads are VERY RESTRICTIVE compared to the AFR heads and the CAMS REALLY TOO MILD for best results..ESPECIALLY IF THE AFR HEADS WERE USED, yet they still make over 70 hp matched to the cam

 

 

heres the better LT4 race version AFR heads

 

 

heres the stock LT1 heads

 

the AFR easily have the POTENTIAL to feed 575-600 HP, at LEAST a 100 hp PLUS advantage over the ported stock heads IF THE OTHER COMPONENTS ALLOW THEM TO FLOW AT FULL POTENTIAL, but in reality they flow enought that they easily out power the EDELBROCKS by about 50hp or more, MUCH MORE on a larger engine displacement

[jnjdragracing]

I would save my money and buy a cam / head package like the eldebrock performer plus package as an example. On another note you will need to see what the stock heads combustion chamber is. example if it is at 68cc then you would want the new heads to be the same or lower, this will keep your compression ratio the same or increase it. When I bought my heads ( eldebrock victor jr alum. heads ) they were 70 cc, then I had them cut down to 64 cc.

 

The cam / head packages seem to be reasonable priced, do not forget the intake.

 

John

[Twoeightnine]

I would save my money and buy a cam / head package like the eldebrock performer plus package as an example. On another note you will need to see what the stock heads combustion chamber is. example if it is at 68cc then you would want the new heads to be the same or lower, this will keep your compression ratio the same or increase it. When I bought my heads ( eldebrock victor jr alum. heads ) they were 70 cc, then I had them cut down to 64 cc.

 

The cam / head packages seem to be reasonable priced, do not forget the intake.

 

John

 

:hail: :hail:

Performer RPM is a good choice for the street. Yep if you have the time, and believe it or not you probably do, save some dough and let er flow!!

The edelbrock packages are a solid choice due to the fact that they are proven "packages". Cams, heads, intakes even carbs, can be matched for your aplication.

!

[Bartman]

There's more to this than just horsepower. The aluminum heads will give you a weight savings of about 50 pounds, which is pretty significant. It all depends on how much money you want to spend and where you eventually want to get too. It doesn't make too much sense to get a new cam that will work well on your stock motor if you're going to be making significant upgrades that will make it the wrong cam for your upgraded motor. If you're going with a cam are you going to go with 1.6 Roller Rockers? Depending on your mileage you will probably need new lifters and the new cam will probably require different length pushrods as well.

 

I agree with saving your money and doing it all at once. I added ported and polished heads, new cam, 1.6 RR, new lifters, new pushrods, swapped to a vented opti, switched to a true double roller and added an electric water pump all at once.

 

If you don't have the money now, just worry about getting a nice intake and exhaust setup and get that thing installed in your Z. You can upgrade it after you drive it for a while.

[LS1 240Z]

the caprice iron heads flow better than LT1 aluminum heads.

 

when you get heads you should get AFRs or LT4 heads. do a cam swap at the same time. it would cost you a total of like $300 more, and save you SOOO much more work, and you would only have to tune it once

[Mike C]

Can't argue with the info, but the question was if he could do one or the other, which one would be best? No doubt the cam and the aftermarket heads would make more power, but the choices were stock aluminum heads (and I read the question as NOT replacing the cam) or cam and iron heads. Obviously, the cam and iron heads is the best choice $ per HP.

[gexgexgexgex]

you guys are always alot of help, what i plan on doing it just puting the motor as is in and doing cam and heads that work great together after a few weeks of runnig.

 

Again thanks for all the info

 

Richard

[280zwitha383]

As usual I will vote against the performer RPM heads/kit. I think you could spend a lot less money and make good power elsewhere but that's just my opinion.