Fitment: 1973-'91 Big Twins. Features & Benefits:Same width oil supply and return gears as the stock HD® aluminum pump. S&S pinion and oil pump drive shaft drive gears increase potential oil volume delivery by 25% over stock on 1972 and earlier engines. Machined with an oil pressure relief bleed off passageway & relieves pressure build up on top of the valve to maintain consistent oil pressure. Oil pressure regulation bypass routes excess oil directly to the supply side of the pump & reduces the amount of oil returned to the tank, less foaming and cavitation. The standard pump cover allows total flexibility for oil system configuration with a number of oil feed and return options.
Chrome Plating the Pump – It is extremely difficult to chrome plate an oil pump without getting chrome in the passageways, cavities or on the machined surfaces where
the gears, check ball, and pressure valve operates. Chrome in these areas as well as on the gasket surfaces impairs the pumps performance by altering the operating
tolerances machined into the parts. In addition, abrasive particles of chrome may break loose causing damage to the pump and the engine. Because of this, S&S does not
recommend chrome plating the pump body or cover. S&S voids its warranty if these parts are chrome plated.