Comp Cams 08-601-8 M-Thmpr 235/249 H-Rolr Cam OE Roller SBCM Thmpr 235 249 H Rolr Cam OE Roller SBC 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