89 L98 Alum. heads

[thirdtimevetteowner]

Can anyone tell me the specs on the aluminum heads, such as combustion chamber cc's, intake runner cc's, exhaust runner shape and cc's, valve sizes, and valve spring O.D., inst'd seat preassure, max lift, coil bind? Any help with this extensive list will be surely appreciated. Thanks all.

Rich K.

 

[Ken]

http://purplesagetradingpost.com/sumner/techinfo/heads1.html

 

[thirdtimevetteowner]

Ken,
Thanks for the great, organized list. Am still looking for more info concerning the L98 heads. Ran (stumbled) across a cite that had some more info on them. They have 163 cc intake runners, 58cc comb. chambers, 1.94 I, 1.50E valves, D-shaped ex. ports and best of all, the ex. to int. flow ratio is way up at 80%. With some porting and bowl-blending, they flow really well. Plus w/the small chambers and flat top pistons, and appropiate deck height, will produce about 11:1 C.R. easily. I just wish they were already off my engine; the thought of tearing it down w/all the computer and electronics makes me kinda cringe, but there is no getting around it, even to install aftermarket heads. If I find anymore stuff, I'll let you know, so if you like you can upgrade the list.

Rich

 

[Ken]

I've been trying to find the runner length specs for you but I don't seem to be getting too far...

GM Performance Parts aluminum cylinder head assemblies are based on brand new Corvette light alloy castings (P/N 10088113). The Corvette cylinder head’s advanced design features include D-shaped exhaust ports that enhance the flow of burned gases, high-velocity intake runners that provide crisp throttle response, and centrally located spark plugs that improve combustion efficiency. Valve seat inserts for 1.94” diameter intake valves and 1.50” exhausts are installed in the 58cc combustion chambers. Raised rocker cover rails with machined sealing surfaces virtually eliminate rocker cover gasket oil leaks. This high-performance cylinder head assembly is used exclusively on High Output 5.7-liter small-block V8 engines.

I'll keep looking.

 

[Edmond]

Wow, the L98 heads flow looks so anemic compared to everyone else!

 

[C4ME]

Ken, do you have a brand of head gasket you would recommend for L-98 heads?

Joe