Raising compression.

Kev'C3

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Joined
Feb 14, 2015
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Hi all you Corvette gear heads. I hope all are doing well! I have a ZZ4 350 sbc with Edelbrock performer (6089) heads. Its a used engine and someone change the heads. I do believe that they are 64cc with 202 intake, 160 ex. The original heads I believe where 58cc with 194 intake,150 ex. The later increased compression to 10:01 while the edelbrocks brings it down to 9:01 but flows better. What is the best way to raise compression by a point or more,mill the Edelbrock heads or change the pistons? I think milling the heads would be the way to go. Changing pistons means disassembling the engine and machining the block. At this point might as well stroke it,for it would be a total engine rebuild! Any comments would be much appreciated. Thanks.:sos:
 
Just some thoughts and I am not an engine builder. Don't assume anything if you did not build the engine. Edelbrock did sell 60cc chambered heads. If the heads were changed what else may have been changed. You would want to confirm pistons, if block has been decked, head gasket thickness before milling the heads. I would warm up the engine and do a compression check. It may give you an idea of compression ratio and whether you want to do a tear down to check. JMHO

Tom
 
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