Part #(MCC547) Installation tips: Make sure you have purchased the correct pulleys for your 396 427 or 454 before mounting them to the engine (pulleys with washer marks or scratches cannot be returned) Material Chrome steel , triple plated Copper / Nickel / Chrome Bolts   Chrome pulley Does Not  come with mounting bolts Thickness The chrome pulley is stamped from approximately .060 thick steel. Diameter  The diameter of this chrome Big Block Chevy Pulley is 7 5/16" Two Piece This pulley is a 2 piece pulley consisting of MCC546 and MCC9817 add on for power steering" Belt Chrome V belt pulley uses a standard 3/8 belt size Water pump  Chrome pulley is for big block Chevrolet 396 427 454 engines with short water pump  (alternator mounted on the drivers side) Grooves  Big Block Chevy chrome crankshaft pulley has 3 grooves Restrictions  Cannot be run on Big Block Chevys with long water pump. Gen 4 only .Cannot be run on Gen 5 or Gen 6 BBC's Comments: We have matching chrome water pump pulleys chrome alternator pulleys and chrome power steering pulleys if you want to complete your engine Check Out these related items