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Old 12-27-2012, 12:24 AM
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The GMPP 383 SBC crate engines have the 3.8" stroke crank and use 5.7" rods. What I can't find is the compression height (CH) of the pistons they use. Looked for both the first and second design part numbers, and found nothing on the CH.

One one forum a guy estimates the CH of his GMPP 383 to be 1.375", but that puts the piston too far down the hole (about 0.050" w/o a head gasket installed). I just can't see Chevy doing this- even though the pistons are crappy round dish, but w/2 instead of 4 valve reliefs. But that's small consolation for the round dish/narrow quench band design.

If the 3.75" stroke/5.7" rod piston CH of 1.425" is used, that puts the piston deck height at zero on an undecked 9.025" block. I really don't see Chevy doing that, either.

So does anyone know what the CH is for the GMPP 383?
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