Complete kit that includes it all. The oil pump assembly complete with mounting hardware; fittings; gaskets; pinion shaft pump drive gear; woodruff key; clip; oil pump shaft driven gear; breather gear & a shim kit. The oil pump is fully CNC machined to maintain close tolerance and strict quality control. OEM width feed and return gears. For the cleanest look possible; this pump is not equipped with a rear chain oiling provision. Note: Drive gears; supplied in this ''Pump Kit''; will fit 84-89 pinion shafts only (models with multiple parts flywheels) and will not fit late OEM 90-99 straight pinion shafts that are one-piece with the flywheels. This kit is designed to be used with models that are custom fitted with earlier (pre-1990) multiple parts flywheels. Note: There may be more differences in Harley-Davidson crankcases than you might think. Plugging or drilling a hole is sometimes necessary. S&S offers a drill jig as MCS 518150. This is a special tool that is mounted on the crankcase and used as a guide to help you drill holes correctly.