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5. We were shooting for an SCR at or slightly below 9.5:1. We measured the volume of the combustion chambers in the head after porting, and the volume of the Sealed Power hypereutectic piston dish in the cylinder. You can measure the dish separately, but in the cylinder, you also see the ring land volume (generally about 1.1 to 1.3 cc). We used the thinner of the two commonly available head gaskets, and after taking about 0.020 inch off the deck for a clearance of 0.025 inch, we ended up with a 9.44:1 SCR and an 0.068-inch quench height: Less than ideal, but it saved any special machining. Had we used the thicker head gasket, we would have dropped to 9.27:1. With the cam we chose (204-degree intake duration, 26 ABDC) our DCR is calculated at 8.7:1.

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