Valick103

I had heard that the plenum (both upper and lower) from a 3100 fwd engine would bolt on to the 2.8 rwd (89 camaro)
I heard this improves the engines ability to breath at higher (4500+) rpms something the 2.8 has trouble with. Can anyone confirm this, has anyone done it?

The_Raven

You've heard very wrong.

The FWD GenII and GenIII top ends need to be swapped as complete assemblies, including heads and some other parts, some being custom.

Here is a picture of an iron head and aluminium head on teh same block for comparison:





And a complete turbo hybrid in my Jimmy:



Those this will be somewhat correct, it will help improve breathing ability, teh small port 3100 intake ('95 to '99) starts to lose breathing ability at about 4500 to 5000 RPM, depending on the required flow.
For best gains use the '00+ 3100 top end or the 3400 top end.

Valick103

Thanks for the info raven. Do u know of anyway to improve on the 2.8's plenum so it can breath better at higher rpms. would porting and polishing be worth it. thanks agian for the info

69charger383

Port n polish helped me alot. I did mine myself so its not that accurate in flow for each runner but it still works pretty damn good. Id recomend finding someone with a flowbench if your gonna do it yourself otherwise send it out.

The_Raven

I haven't personally made any improvments with the genI 660 top end. I have swapped to the genIII 660 top end and see no reason for myself to do anything else.

Valick103

thanks for all the help. I'll be going to the junkyard to pick up a "new" 2.8 plenum to port and polish, i'll let you know in an another post how it came out. thanks agian for the information.

drdave88

iTrader: (3)

what other mods have you done so far? if nothing, theres lots to do before the intake. start w/ the bolt ons. if you know how to P&P, go for it, otherwise id start w/ the easy stuff first.

Valick103

well so far not alot, i have a cat-back exhaust system (dynomax), AC delete and thats it. this spring, i'm going to install pacesetter headers, 1.6 rocker arms, cam, and CAI (unless the slp lid will fit. ne idea?). I've never ported or polished n e thing before but my father has many times and he can show me how. Thats also why i want to get another plenum so i can spend the time to make it nice. with the mods i mentioned above how much power do u think i'll be making? i figure around 150 (30+ over stock) does that sound unrealistic?

dbtk2

Personally I'd do a complete large port 3x00 swap. Its a lot of work but would provide a nice gain. Since you've already gotta pull the intake & front cover to put the cam in anyways, you might as well just pull the heads and change everything right then. You'll like the gains and in the end it will be well worth it. I did the swap on my '90 GP (went from the older gen 3.1 topend to the newer small port 3100 stff) and I noticed a nice gain. I noticed a 7 tenth and 5mph gain in the 1/4 with the heads/intake swap, plus an UD crank pulley, and a cam. But I also went from 12.5 to 8.5psi boost also.... Keeping the 12.5psi boost I suspect would've netted me a full second gain and 6-7mph in the 1/4.

I know this is a completely different situation then yours, but you will definately see nice gains.

Shawn

85berlinetta2.8

to my understanding with the newer heads you cant use the regular headers so you need to have some made. you cant use the lower intake manifold you need to have one made. with the newer plenum you cant use a distributer so you need to install direct ignition system. if im wrong please correect me.

Valick103

from what i've heard there is a lot that goes into swapping to a 3x00 topend. Snice i'm in college (no money) and this is my daily driver (gets me to school and back) i can;t really spend the time needed to fab parts or to risk having my car up for weeks. On a side note i saw on e-bay some aluminum heads for the 2.8, while they didn't mention fitting on the camaro, (just cavi and other fwd) i wonder if they would. I imagine the weight loss would be enought to justify them ( i think they were around 200). I'll try and find them and post. Oh i was thinking that a bunch of us should get together and make a 2.8 pdf for questions like mine, give back alittle to the community and all.

85berlinetta2.8

i do agree that there should be a sticky with actual facts and pictures regarding fwd 2.8 aluminum heads and intake on rwd cars. and i also believe both ked85 and dale 3.4 swap directions should be stickies as well.

i dont think those heads would work. you need to look at the exhaust ports and see the 0_0_0 oppsosed to 00_0

The_Raven

The Exhaust layout is EXACTLY the same for all OHV 660s, the difference being that the aluminium head version have the studs farther apart than the iron head, and the genIII uses a D-shaped exhaust port as opposed to the round ports of the genI and II.

Yes there is a lot that goes into swapping an aluminium top end into a RWD vehicle.

The info on dizzy interferance is correct, the stock genII and III intakes do not allow for a stock dizzy to be used, a modified dizzy could be used or a modified intake could be used to clear the distributer, but either way will take extensive modification.
Starting with a 3.4 block, or fabricating a crank trigger will be needed to get the DIS ignition to fire, also an ECM swap will probably be needed, I haven't attempted to run my DIS on a dizzy ECM yet, to verify this.

The genII 2.8L heads are closer to the genIII heads than the genI, meaning that it's as much work to swap genII heads in a Camaro as it would be to swap in the genIII heads.

Derickab

Here is a little reading before you spend any money. There are also a few articles in CarCraft magazine that I read up on. Since I just rebuilt my engine I looked into going with aluminum heads but was told by afew mechanics that they it wasn't worth the money. Of course the aluminum heads are lighter and I was thinking along the same lines but I was given some tips on a few other things to do that would make my ride better buy spending that money else where. The choice is yours just giving my 2 cents.

http://chevyhiperformance.com/techarticles/83858/


http://proformanceunlimited.com/heads.html

The_Raven

Ok, the Chevy Hi Perf article supports that Aluminium can make more power, even when both heads are essentially "identical", which we should all realize is near impossible.

The transfer of heat could be a good thing, why do people want to run thier engines at such a high temp that metal could actually deform? I do however agree that too cold is probably worse.

But the article really can not be applied to the 660, since there is a VERY large difference in flow characteristis between the iron head and aluminium head versions. The aluminium head versions flow a substantial amount more than the iron head 660 head. The combustion chamber is just over all shaped better and more squeeze (SCR) can occur, with a better shaped piston to pormote the use of the flame front over what would have to be done with an iron head version.

Also the second article supports the use of aluminium heads, due to the weight savings, which will never be seen on a dyno, but in lap times.
On the 660 there is a good 60 lbs difference in static weight alone when comparing the heads.

Better flow, lighter, what's to lose?

Derickab

To Raven,

You are right about that. Thats the issue I ran into, everything I readup on was on v8s. Not much info to inform you about the 6s. So I stuck with what I had. After looking over a few threads on here I wish I would have gone with the aluminum heads. Thats ok it will keep my insurance down. LOL

Valick103

For practical reasons the aluminum heads are out. So know that i know i'll be using the iron heads whats the best way to get more out of them? I've heard of the HO ones but i;m not sure if they were on a production car (junkyard!) if they weren't i'm asumming they'll be way to much new from gm. What about port and polishing the stock heads? thanks for all the info and articles

85berlinetta2.8

heres some good guides for general head porting, i know its for v8's but the information can be applied. i will be doing this when the exhaust leak at my manifolds ruin my valves and i have to have everything taken off. anyone knoe what a burnt exhaust valve sounds like? sounds like a backfire on decceleration doesnt it? i have that. hahah.

http://www.cmc.net/~xero/Mousesporting.html

http://www.sa-motorsports.com/diyport.shtm

https://www.thirdgen.org/techbb2/sho...hreadid=117410

lower intake porting

http://www.tmossporting.com/TechArti...8/Default.aspx

The_Raven

The "HO" designation for the genI heads only applies to pre '85 (or '86) heads, after that, all heads were "HO" heads, same porting, same valves, etc.

Valick103

Glad to hear that raven, guess i'll be going to the yard to pick some up and port and polish them!

85berlinetta2.8

what was so special about the HO heads?

The_Raven

Nothing now.

The "HO" heads had an increased valve size to 1.72 and 1.48 (I think those are the right sizes, I can't believe I don't remember that :S), from 1.65 and 1.42 IIRC.