This 3-5/8" big bore kit may be used to replace the cylinders and pistons of an S&S SH93 high compression engine or a stock HD shovelhead engine that has been upgraded with an S&S 93" Hot Set Up Kit . This kit may also be used to upgrade an engine with an S&S 84" stock bore stroker kit to 93". Stock crankcases must be bored to accomodate the 3-5/8" bore cylinders, but the 4-1/2" stroker flywheel assembly does not need to be rebalanced. The kit includes S&S 3-5/8" bore cylinders, 3-5/8" bore forged pistons with rings and wristpins, head gaskets, base gaskets, exhaust gaskets, and instructions. Compression is 9.1:1. The cylinders are longer then stock , so longer pushrods, and manifold must be used.