Our Big Bore "Sleeper Kit" turns your Twin Cam 88 into a Mean Machine The use of these 4" bore "Sleeper" pistons in conjunction with a 4 3/8" Stroker crank you enlarge the capacity of the standard Twin Cam engine from 88 to 110CI. Stock cylinders must be re-sleeved, and crankcases have to be bored to accept the Big Bore sleeves. No cylinder head modification is required. Kit includes a pair of Wiseco forged pistons, piston rings, retaining clips, piston pins, and gasket kit. Big Bore cylinder sleeves and stroker crank must be ordered separately.