Billet Aluminum Pontiac Power Steering Pulley, 350 - 400, 428, 455, V-Belt Pontiac Big Block Crankshaft Pulley, V-Belt, 1 Groove (350 - 400, 428 & 455) Made in the USA from 6061-T6 Billet Aluminum Shaft Diameter of 5/8" - Keyway Fit Offset (distance from front of pulley to center of 1st V-groove) is 0.925" Pulley Diameter of 5.8"