i just got a set of '90 vette L98 aluminum heads that i am going to put on my engine.
does anybody know if its ok the use the standard square port shaped headers on these d-port heads. or where can i get some d-shaped headers for a third gen. also a comp cam with 210/220 dur. and .480/.480 lift is going in. heads are mildly ported with valve job.
anybody done this before.
what do you think?
shooting for high 13's at least 100 mph with the automatic tranny. ya think it'll work?

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88 CAMARO RS
87 IROC-Z DRIVETRAIN
305 TPI, 700R4, 3.73s
ported plenum, performance resource chip,edelbrock TES Headers and cat-back, K&Ns, AFPR, rest is stock.
15.0 @ 92.5 (bald tires)

 

you should forget your headers worry and look at the chance of the valves hitting the deck. the 350 heads have a larger chamber than 305's. you'll also lower your compression due to the larger chamber size.

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-=ICON MOTORSPORTS=-
1st & 3rd

 

no the heads will work.
the chambers are 58cc, same as the stock 305 to my knowledge. the valves are not any larger the stock heads either 190 intake and 150 exhaust. compression will stay the same unless i change to another gasket.
thanx for reply.
there is a guy on the board, i think his name is david tushnof or something, did this setup. his car was in gm high tech performance. ran 13.6@101 on motor!

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88 CAMARO RS
87 IROC-Z DRIVETRAIN
305 TPI, 700R4, 3.73s
ported plenum, performance resource chip,edelbrock TES Headers and cat-back, K&Ns, AFPR, rest is stock.
15.0 @ 92.5 (bald tires)

 

There is no need for any special header. You will find that even a small header is still larger in diameter overall than the port is.
My Edelbrocks clear completely.
Roy

 

isn't the distance across the chamber wider on a 350 than a 305? sorry i don't have any 305 heads laying around to check. i know the 283's were smaller than the 327 and 350 heads in that respect. only thing i've ever done with a 305 is swap it for a 355.

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-=ICON MOTORSPORTS=-
1st & 3rd

 

While the valve sizes are the same on the 305s and 350 heads, the valves on the 305's are closer together. Trust me. This is from Smokey Yunick's book. You probably will have deck clearence problems.

 

Smokey died before he saw any tpi 305 heads. This setup will work and run good but 13's might be pushing it unless you can get the computer setup just right. I have heads of a 89 vette on my 90 305 in my 85 s10. They work great. You will be happy.

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87z 383,afr 190's, crane hyd roller(224/230-.509/.528,112 sep),Ported and polished mini ram, 24lb inj, 3.42 gears, strange 12 bolt, tremec 5spd, , 1,3/4" slp headers.(stock 305 hypercrap chip), other stealth goodies.
Runs 14's all day long.

 

Actually, the intake valve is larger on the Aluminum Vette Heads (1.94 vs 1.84). Exhaust is the same.

But the Vette heads will work. Ask Willie. He's got Vette aluminum heads on his 305 and can explain if there is anything special he had to do to make them work with his 305.

 

THANX GUYS FOR ALL YOUR INFO.
I CHECKED WITH THE LOCAL ENGINE BUILDER WHERE I'M GETTIN THE HEADS REBUILT, HE ALSO SAYS THEY WILL WORK WELL.
ANY SUGGESTION ON A HEAD GASKET?
SHOULD I GET ONE FOR A 305 OR A 350?
WHICH THICKNESS DO YOU SUGGEST, I WANT TO KEEP THE COMPRESSION ABOUT STOCK.
DO YOU USE SILICONE ON A HEAD GASKET?
THANX AGAIN.

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88 CAMARO RS
87 IROC-Z DRIVETRAIN
305 TPI, 700R4, 3.73s
ported plenum, performance resource chip,edelbrock TES Headers and cat-back, K&Ns, AFPR, rest is stock.
15.0 @ 92.5 (bald tires)

 

Damn! Smokey is going to be awfully upset to find out he died! And nobody even told him about it! LOL

 

Is it true that the Vette heads don't have a heat cross-over passage? If so, that means the EGR would not work on a standard manifold.

 

YEAH, THERE'S NO EGR PASSAGES ON THESE HEADS.
WILL I HAVE COMPUTER PROBLEMS WITHOUT EGR?

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88 CAMARO RS
87 IROC-Z DRIVETRAIN
305 TPI, 700R4, 3.73s
ported plenum, performance resource chip,edelbrock TES Headers and cat-back, K&Ns, AFPR, rest is stock.
15.0 @ 92.5 (bald tires)

 

You MIGHT have problems without the EGR. I doubt it will throw a code as long as all the EGR "stuff" is still there and working (although no EGR gas will actually be flowing through it). More likely the engine will simply have a greater tendency to ping at part throttle. A custom chip can eliminate the EGR completely if you find you can't live with it like that.

Does the 87 use the 9th injector for startup? I can't remember. If it does you might want to think about that, too. My brother mentioned to me once that the 9th injector is tied into the crossover passage somehow. I don't honestly know. Maybe someone else could confirm/deny that. Anyway, the 9th injector can also be deleted with a custom chip if you need to go that way.



[This message has been edited by Damon (edited November 22, 2000).]

 

The 9th injector has its own passages.

As for gaskets and such...

Silicone? Might I suggest buying a book on rebuilding engines. The head gaskets you are going to find go on dry. Aluminum heads require a special gasket so make sure you get one that is for aluminum heads.

ede--- the chambers are relatively small on the vette heads. The design is much more like a 305 design than a 350 design. The only problem area I can see would be near the exhaust valve, the chamber goes over pretty far there. Might need to use a 350 gasket, which is what I think Willie did.