Fits 99-06 88" Twin Cam with stock cylinders that have been bored to 3-7/8"; and equipped with 4-1/2" stroker flywheels. Gives 9.7:1CR with stock heads. The forged pistons have a flat top; weight is same as stock. 1.020" deck height. Also as replacement for S&S 106" Hot Set-Up kits. Crankcase boring and re-balancing is not required and pistons are compatible with S&S and stock cylinder heads. Complete with pistons; 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.