Compression

Thanks Ram...I'm at 0' elevation...lol. You guys can "get away with" some higher ratios, but I'd still prefer living near the shore ;). A note on the .040 distance. I've run as close as .030 with good pistons, good crank, and steel rods. I know of several racers who run as tight as .027, but they can read the piston part number stamp like a mirror in the cylinder surface. They actually barely touch at 7K rpm. At least, that's what I am told. Generally, .035 to .045 is what you want. The closer, the better the effect.