COMP Cams 7101 Keyway Adjustable Billet Timing Set for Big Block Chevy Gen VI Induction hardened and precision machined steel billet gears for bullet proof durability Feature 9 keyway crank sprocket for 2-degree incremental adjustability, 8-degree maximum advance/retard Pre-stretched, heat-treated double roller timing chain with heavy-duty large pin design Includes Torrington roller thrust bearing for reduced friction