Comp Cams 01-602-8 BM-Thmpr 243/257 Hyd Roller Camshaft for BBC GEN VIBM Thmpr 243 257 H Roller Cam BBC GEN VI Designed to deliver an aggressive, hard hitting exhaust note at idle, the Thumpr camshaft series from COMP Cams also delivers excellent horsepower gains and a broad torque curve. A perfect choice for muscle cars and street rods, the Thumpr series' early intake valve opening and long exhaust duration create optimum overlap for that race car idle. The Thumpr grinds all require an aftermarket torque converter and