Competition Cams 12-602-4 Big Mutha' Thumpr 295TH7 Camshaft for Small Block Chevy HYDRAULIC - Big Mutha' Thumpr: Street/strip, needs 9.5:1 compression, 2800+ stall, intake, gears and headers, very rough idle. 295/313 Advertised Duration, 243/257 Duration @ .050 inch, .500 inch/.486 inch Lift, 107 Lobe Separation Valve spring upgrade required