Hello,

I am in the process of building a ZZ430 clone engine. In case you are not familiar, this was simply a limited edition engine built by Chevrolet I believe over 10 years ago. It was simply a ZZ4 shortblock with Fast Burn aluminum heads, LT4 hotcam and 1.6 Roller Rockers. Anyhow, I have the ZZ4 short block and am getting ready to bolt on the heads. I am going with the GM performance headgaskets. But I have two choices: 10105117 or 12557236. Now the ZZ430 apparently came with the 12557236 gaskets which are 0.051" compressed thickness. The ZZ4 crate engine piston deck height is apparently .025 which would net me a quench of 0.076 correct??? I would assume this is far from ideal quench goal of around .040? Anyhow the 10105117 gaskets are 0.028" compressed thickness. I would assume this would net me a quench of .053 which would not be perfect but much closer. Am I looking at this all wrong??? I want to use the thinner gaskets if I can get away with it. I do have 93 octane out here so I have no issues using that all the time. I would assume that my engine is similar to the new ZZ5 crate engines which use the thicker 12557236 head gaskets and are 9.72:1 compression. So I would imagine I would have no problem using the 10105117 gasket depending on how much it bumps compression??? Any help would be appreciated. I'm ready to bolt on the heads but need to make sure before I assemble. Thanks everyone in advance!