Need help with compression and head gaskets!
09-29-2008, 11:27 PM
#1
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Need help with compression and head gaskets! I am rebuilding my Ls1 from my 2001 Z28. I will be using stock crank, rods and pistons. But I am adding a Stealth II cam 224/220 .581/.581 116LSA and stage 2 ported 243's. The 243's have NOT been milled.
Should I mill them or will this be enough compression?
Which head gasket should I use and what thickness?
Thanks,
Brian
Should I mill them or will this be enough compression?
Which head gasket should I use and what thickness?
Thanks,
Brian
09-30-2008, 12:09 PM
#2
With 66cc chambers and .056" head gasket SC=10.36 DC=7.73
With 66cc chambers and .040" head gasket SC=10.76 DC=8.02
With 64cc chambers and .056" head gasket SC=10.61 DC=7.91
With 64cc chambers and .040" head gasket SC=11.04 DC=8.22
With 62cc chambers and .056" head gasket SC=10.88 DC=8.10
With 62cc chambers and .040" head gasket SC=11.33 DC=8.43
The .056" head gasket is the GM MLS, and the .040" is a Cometic. I think that you would be conservative with 64cc chambers and a .040" head gasket, but if you have access to 93 octane gas, you could step up to the 62cc chambers with .040" gasket for a few more horsepower. The thinner Cometic gasket will improve your quench volume, which reduces detonation. Your camshaft is not quite optimized at 8.4 dynamic compression ratio. That profile has -10° overlap at .050" lift...
With 66cc chambers and .040" head gasket SC=10.76 DC=8.02
With 64cc chambers and .056" head gasket SC=10.61 DC=7.91
With 64cc chambers and .040" head gasket SC=11.04 DC=8.22
With 62cc chambers and .056" head gasket SC=10.88 DC=8.10
With 62cc chambers and .040" head gasket SC=11.33 DC=8.43
The .056" head gasket is the GM MLS, and the .040" is a Cometic. I think that you would be conservative with 64cc chambers and a .040" head gasket, but if you have access to 93 octane gas, you could step up to the 62cc chambers with .040" gasket for a few more horsepower. The thinner Cometic gasket will improve your quench volume, which reduces detonation. Your camshaft is not quite optimized at 8.4 dynamic compression ratio. That profile has -10° overlap at .050" lift...
