S&S Cycle 66-84 BT 80in 3-1/2in Bore Cylinder and High Compression Piston KitThis kit is intended to replace the cylinders and pistons of a 80" shovelhead engine and increase the compression ratio to 9: 1. Compatible with stock or S&S cylinder heads. Kit includes S&S 3 1 2" bore high tensile cast iron cylinders, 3 1 2" bore forged high compression pistons for 80" (4 1 4" stroke) engines with rings and wristpins, head gaskets, S&S stainless steel head bolts with washers, base nuts, base gaskets.