COMP Cams CL12-601-4 Mutha' Thumpr 235/249 Hydraulic Flat Cam and Lifter Kit for Chevrolet Small Block High performance street/strip, needs 9:1 compression, 2500+ stall, intake, gears and headers, rough idle. 2,200-6,100 RPM Operating Range 235/249 Duration at .050". 107 Degree Lobe Separation Angle. 0.489"/0.476" Valve Lift CL Kits include a camshaft, a set of lifters, instructions and assembly lubricant. Early intake valve opening and long exhaust duration create optimum overlap for powerful, hard-hitting exhaust note. Best with aftermarket converters and more rear gear. Perfect choice for muscle cars and street rods - Three unique cam designs: Thumpr, Mutha' Thumpr and Big Mutha' Thumpr deliver excellent horsepower gains and broad torque curve. Fits Chevrolet GEN 1 Small Blocks including the 262, 265, 267, 283, 302, 305, 307, 327, 350 and 400. Does not fit LT1/LT4, or factory roller Small Blocks built from 1985 and newer. Made in USA