Chain drive. 618 F CAM - Race Series Camshaft. Requires large bore size; ported cylinder heads; ported intake manifold; high flow valves and large throttle body. Aggressive camshaft requiring high lift and higher load valve springs (like Feuling 588022); performance pushrods (like Feuling 993528) and lifters. High flow air cleaner and triple stepped exhaust pipe highly recommended. Feuling recommends matching this cam with Feuling''s Race Series oiling system 707407 or 707410.. NOTE: High lift/High Load valve springs required see recommended Feuling HIGH LOAD BEEHIVE valve spring kit 588022. Heavy duty pushrods 993528. Clearances MUST be checked when installing this cam.RPM range 3;100 - 6;650. Grind: 618...............Valve Lift Open Close Duration @ 50" TDC Lift Lobe CenterlineIntake .608 20 42 242 195 101 Exhaust .618 65 19 264 170 113Overlap: 39Lobe Separation: 107