This oil pump features the same oiling pattern as the 1981-99 Big Twin engines Features a split oil path that applies more pressure to the top end for longer component life Great for the custom builder with multiple oil ports for a variety of plumbing options Kit includes billet oil pump, supply and return gears, drive shaft with keys and snap rings, check ball and spring, pressure relief valve and spring, check ball and relief valve cover screws with o-rings, gaskets, fittings and hardware No provisions for rear chain oiling Fits all Big twin models 1973-91 Installation on pre-1981 models requires drill jig 740-613 During service or rebuild S&S Cycle billet oil pumps require gasket kit 740-504, OEM gaskets are not compatible