Quote:
Originally Posted by tll74
Nearly all pistons are destoked. Ive seen pistons on sbc's be as low as .060 down in the hole. This is a compression killer. I believe most, if not all, compression advertized spec's are based on zero deck height and a .038 head gasket. I would deck the block to near zero to obtain .040-.045 "qench".
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I'll respectfully disagree with a few of these comments. Compression height is 1.560; the only reason for a "shorter" piston is to compensate for a significant cut to the block deck. If the piston is at anything other than .025 standard deck height (block deck of 9.025) then someone ordered the wrong piston.
Compression is usually expressed at standard deck (.025) for hypereutectic pistons, and at zero deck for forged - but you MUST check the specs and not assume. The standard compressed gasket thickness is typically .039.
While I agree that an .040 quench is ideal, it's not quite as simple as just zero-decking the block - this is a decision that's made as part of the overall build. Note that you can achieve the same quench by using a thin steel "shim" gasket at .015 compressed thickness...combined with an .025 deck, there's your .040 quench. All that's required is a very smooth deck and head surface; you just need to let the shop know that you'll be using these types of gaskets.
Lots of ways to skin a cat, but the important thing is to PLAN the build and build to the plan.