comp cams camshaft, mutha' thumpr, hydraulic roller, advertised duration 283/303, lift .563/.546, gm ls gen iii/iv, each

COMP Cams has awakened the muscle car sound--and it is nastier than ever! Thumpr Series camshafts is a line of cutting-edge hydraulic roller camshafts for engines originally equipped with flat tappet cams. With them, you can expect a substantial power increase without sacrificing reliability or ease of maintenance! The lobe profile and grind characteristics of Thumpr cams include blending an early exhaust valve opening, a long exhaust duration, and a generous amount of intake and exhaust overlap. This maximizes rough-idling tendencies, delivering a seriously aggressive exhaust note without affecting engine power output. Thumpr camshafts are available in a variety of grind profiles, each producing impressive horsepower and torque performance within a different rpm range.