COMP Cams Hi-Tech Roller Race Timing Sets include cast iron camshafts gears, induction hardened billet steel crank sprockets, and pre-stretched, heat-treated double roller chains with heavy-duty large pin design. They feature 3 keyway crank sprockets for 4? incremental adjustability with 4? maximum advance or retard. These timing sets are dynamically balanced and quality checked for run-out tolerances.