COMP Cams CL96-601-5 Mutha' Thumpr 235/249 Hydraulic Flat Tappet Camshaft & Lifter Kit, Buick 400/430/455

COMP Cams CL96-601-5 packages the Mutha' Thumpr 235/249 hydraulic flat-tappet camshaft with its matching lifters for the Buick 400, 430 and 455 engine family, covering V8s built from 1967 to 1976. At .050-inch lift it measures 235 degrees of intake duration and 249 of exhaust, with 287 and 305 degrees advertised and a 107-degree lobe separation angle, giving it the choppy Thumpr idle this series is known for.

Where this grind operates

COMP places the usable range at 2,200 to 6,100 rpm, well above a stock street cam and squarely in street/strip territory. It is not a swap-in-and-forget part: COMP calls for at least 9:1 compression, a converter stalling at 2,500 rpm or higher, an intake sized for that rpm range, and rear gearing and headers that match. Weigh your Buick's current combination against those four points first, since a cam this lumpy dropped into a low-compression engine on a stock converter will idle worse and pull less down low rather than more.

What's in the box

The kit pairs the camshaft with its own matched hydraulic flat-tappet lifters, so lobes and followers do not need to be sourced separately. It suits a Buick Nailhead build already aimed at strip use, where the rough idle and the top-end pull are the point rather than a side effect.