S&S Cycle 107 Big Bore Kit Features: Silver or Black finish The largest bore, 3.937 that can fit into a stock engine Bolt on kits make installation as easy as possible There is no machining required for the case nor do the pistons require boring or honing Cylinders have 11 fins and are designed to resemble the OEM shape and color. Each cylinder liner is centrifugal cast, and features 40,000 psi tensile strength for superior wear and performance CP pistons, industry leaders, complete this kit and provide exceptional wear, noise characteristics, as well as performance Pistons are complete with rings, wristpins, and wristpin clips Comes with top and bottom cylinder gaskets