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I'm ready to take my 440 block in to be decked, (already bored, honed and aligned honed). I am installing Diamond forged pistons and was using their C.R. calculator to figure my static comp ratio. Their number seems a bit high and I was hoping someone smarter than me (not hard to do ) could double check my figures. My numbers are as follows: Bore 4.350, Stroke 3.750, Rod Length 6.760, Gasket Bore 4.500, Gasket Thickness .039, Top Ring Down .240, Valve Relief -4cc, Chamber Volume 84cc, Proposed Piston to Deck Height .005. Diamonds calculator shows that combo adding up to a static CR of 10.89 to 1 . The heads are aluminum (440Source). Thanks.

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The diamond calculator rates your motor at 10.1 not 10.89.you put in the wrong info.-4 for dome + 4 for dish. valve reliefs would be a dish not a dome.Try +4 instead of -4 and you will see your compression ratio is around 10.1 to 1 cheers Rob.