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Do not confuse "Pinch"  with compression.     two different things   cylinder pinch or taper is just that its tighter at top dead center and with most sport engines that are set up rather mild the pinch will gradually become less noticible when turning over by hand or completely disappear early on.      That does not mean it has lost compression.</p>

Trying to improve performance by loosing a gasket usually ends in frustration but try it if you want.    There is no reason to replace cylinder bolts if they are not damaged.</p>

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John</p>

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