S&S Cycle SS91-9012 74ci High Compression Cylinder Kit w/3-7/16" Bore Black for Big Twin 66-84This kit is intended to replace the cylinders and pistons of a 74" shovelhead engine and increase the compression ratio to 9: 1. Compatible with stock or S&S cylinder heads. Kit includes S&S 3 7 16" bore high tensile cast iron cylinders, 3 7 16" bore forged high compression pistons for 74" (3 31 32" stroke) engines with rings and wristpins, head gaskets, S&S stainless steel head bolts with washers, base nuts, base gaskets