GM Billet 2 Groove Keyway Power Steering Pulley Part #(MCC921) Installation tips: Make sure that you have a keyway pump. It will have a notch in the shaft and the pulley will be held on to the power steering pump by a nut (NOTE: pulleys with washer marks or scratches cannot be returned) Material Billet Aluminum CNC machined Hole Size This pulley is for a 5/8 shaft which is the size all GM keyway style pumps are Keyway This Billet Power Steering Pump Pulley is for keyway style power steering pumps Nut   Billet pulley Does Not come with mounting nut your stock nut will fit the same Diameter  The diameter of this billet 2 groove Power Steering Pulley is  5 3/4" Two Groove This pulley is a 2 Groove pulley for GM keyway power steering pumps Back Space This pulley has a 1 1/8" back spacing Belt Billet V belt pulley uses a standard 3/8 belt size Application  Billet power steering pulley is for Olds Pontiac Small and Big Block Chevy Restrictions Cannot be run on press on style power steering pumps Comments: We have matching billet water pump pulleys billet alternator pulleys and billet crankshaft pulleys for Chevrolet engines if you want to complete your engine Check Out these related items