RedneckJeep

Here's the thing. Throwin ALL the computer stuff out the window (which you really cannot do), your biggest problem with earlier heads is valvetrain failure. Broken rocker pedestals, broken rocker arms, crapped up pushrods and even some dropped valves plagued those earlier engines. I wouldn't touch the earlier heads with a 10 foot pole. Also, as another poster stated, you'll get nowhere porting heads without at least a better camshaft, which no one makes. Of course, you could pay for a regrind, but then, you have to worry about all that other hot rod stuff like increasing air IN (larger throttle body), increasing fuel flow with bigger injectors, better exhaust...which to my knowledge is the only thing available as of now, not to mention a PCM program change. I'm not sure there's a programmer on the market good enough to handle an engine with all the proper mods mentioned above to take advantage of the ported heads. I'd like to see someone cobble up a sheet metal intake manifold, slap a Holley 650 on one, light it up with a crank trigger, bypass the computer and see how it would run. I bet it'd run like a bitch in heat, but I ain't screwin up my Jeep to find out. Face it, they ain't race vehicles. They were never meant to be.

frankie945

Right on.

highoctane

Geeze how much misinformation is gonna be posted in this thread. Ill ket someone else explain why but I will say most def not true. Duration, lift, lsa, etc all effect where the cam will make power.

frankie945

up high that's it. I have put cam's in many cars and all the benefits are in the upper rpm's. Yeah you might get a loopie idle and it sounds mean. But cams only strive in peak of the power band. You might be able to change your redline to 6400rpms. And that would be pushing it on the little 3.8L unless you built the bottom end.

spinlock

I agree with Redneck, what about the little black box known as the PCM?

Does anyone know how to reprogram the brains of the powertrain or are you just going to cram as much air and fuel down the intake ports as you can and hope for the best?

JPop

Just go to comp cams website and look at the cam profiles. Same motor, they can be all over the place. From low end torque hauling cams to high rpm race cams all for the same motor.

highoctane

Correctumondo! There is a such thing as a street friendly cam. And not to forget rv/truck cams specifically DESIGNED to boost low end and mid range power in a vehicle that specifically has those needs, with a power band of like 1000 to 4500 rpm.

frankie945

Well, I guess I'm just used to FI applications. Because the rule of thumb to get more hp up high and to raise your rev limit. Cams are needed to get there.

RedneckJeep

All you need is a camshaft of 220-240 degrees duration at .050" with around .500 or so lift ground on 110 or 112 lobe centers and that would set it on fire on the bottom end....BUT you'd need all the rest that ain't available yet.

lilviper95

just out of curiosity frank, what were the cars that you were putting cams into? I have installed cams in a wide variety of vehicles from 4 cylinders to v8's fuel injected and carb'd and have seen significant gains in the low end, mid range and top end....all depending on the motor they were installed into as well as the specific grind of the cam.