S&S, M8 107" to 124" big bore piston kit. +.010" 18-23 107" Softail 17-23 107" Touring

11.1:1 compression ratio. Piston kit includes forged pistons rings wristpins and clips. Crankcases do not require boring. Big bore 4.250" cylinders are required OEM cylinders can not be bored to 4.250". 107" to 124" pistons come with 1.143" deck height and are compatible with the OEM 107" 4.375" stroke.Note: For 4.250" big bore cylinders only see S&S 574121 (black wrinkle) or 547122 (black wrinkle with highlighted fins). Note: Gaskets are sold separately as 591055 head gaskets 591054 base gaskets or 591056 head & base gasket kit. Note: S&S recommends an S&S 550 series cam which are available in both chain or gear drive. Note: In any and all applications the technician must be able to judge components for their suitability in combination with the other engine components prior to installation. It is of importance that a knowledgeable mechanic will install & make adjustments as required. The rider must follow standard break-in and riding procedures for overhauled engines. 18-23 107" Softail 17-23 107" Touring