Chevy small block Machined finish aluminum billet 6 groove serpentine Crank, Water pump, Power steering, Alternator pulleys set. These are for the Chevy small block long water pump 265-283-305-307-327-350-383-400 engines. The pulleys are CNC-machined from the lightest, most durable materials possible; 6061-T6 aluminum billet. TThe crank pulley are in 6 3/8" diameter. The Alternator pulley are in 4 3/8" diameter, The water pump pulley are in 5 7/8" diameter and The power steering pulley are in 5 3/4" diameter. NOTE: Does not work with stock brackets.