Costs heads and new valvetrain

[skeeterone2]

Okay... This summer im going to be taking the leap and changing my car from auto to manual and im on a limited budget so i was wondering how much it would run me to get iron heads and a roller rocker valvetrain for my 92' 3.1L ... and where do i find iron heads... and what maifold will fit them?.. thanks for your help.

[SappySE107]

Why iron heads? You can use them, and find them dirt cheap on ebay or fiero.nl im sure. You will need to run any of the iron head manifolds, but the 3.4 camaro probably has the best one. Im not sure why you want to go this route.

[skeeterone2]

i would want to go iron because from what im gathering if i ever want to put a turbo on my car that iron heads and a camaro manifold are the way to go... but i dont knw how they will be in the mean time.

[SappySE107]

nah, actually the 3100 heads and pistons are the way to go. If you are talking about 400 hp or something, im not sure what the aluminum heads breaking point is but I really doubt you have to worry about it or swap to iron heads to avoid issues. The iron heads will require a shitload of porting to get them to flow more than stock gen 3, let alone ever reaching ported gen 3 heads. Curtis has the setup you are talking about. Looking at the 750 hp engine posted a little while ago, it has aluminum heads.

[geoffinbc]

Yea there is no advantage in going to iron. The new aluminum heads will handle anything you can throw at them.

Plus they are lighter, flow WAY more, have bigger valves and support self aligning rockers.

[skeeterone2]

http://www.turboz24.com/ <----- he has iron heads... and a camaro intake maifold... and i dont know why he didnt go with the 3100 heads and manifold... he did say he ported them.... but i wonder if it is better than 3100 heads and manifold after porting.

[skeeterone2]

okay thanks.

[TurboZ24]

Yea there is no advantage in going to iron. The new aluminum heads will handle anything you can throw at them.

The comments I got from some TGP guys is that they have cracked at higher boost levels (3.1 heads). GM suggested not using the aluminum heads for high power applications too, but until someone tries it, we will not know for sure.

The iron heads are definately stronger, but stock they flow like crap. Mine currently flow 229 cfm intake/200 cfm exhaust at .5" lift, but they are ported like mad. Normally they flow in the 120-140 cfm range. The iron and aluminum 3.1 heads have the same valve sizes.

I also used them too allow for the valve springs I run, the intake manifold I decided on, etc. I had too clearance the lower intake manifold too clear the lifters, they would never clear the aluminum head lower intake manifold.

[geoffinbc]

Yea I was looking at that solid roller setup you had there. Pretty sweet.

Well having seen that 750HP motor running the Gen III aluminum heads I would have to think they are able to handle any streetable power.

Does anyone know the cause of the cracking? Was it heat or pressure.

Iron is for sure better at handling both, but the aluminum is for sure up to snuff for a street machine.

[TurboZ24]

Well, I do know at what point the flat tappet cam fails, as well as the headgaskets, and several other components except the heads, so there are several other issues before you get too the heads.

On that motor, I wonder when it develops all it's power. I mean if it get's it at 6000 rpm, that's a lot, but if it all happens at 8000-9000 rpm, that's a different matter. It seems unrealistic with that expensive an engine that they would simply slap worked over stock GM heads on it.

You also have too remember that we have to different characteristics we are looking for. For a street car, you want high HP with 50,000-100,000 K worth of reliability in there, racing motors, who cares if it only lasts 1 race. The majority of the problems I had with failures were sustained runs at max power.