Fits 99-06 Twin Cam as a 88" to 95" big bore conversion. Stock cylinders must be bored to 3-7/8" big bore; other modifications not required. The forged pistons eith 5.3cc ''Pop-Up'' dome increases compression ratio to 9.8:1 with stock or S&S heads. 1.270" deck height. Crankcase boring and re-balancing is not required and pistons are compatible with S&S and stock cylinder heads. Complete with rings; wrist pins and clips. 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.