COMP Cams CL33-602-11 Big Mutha' Thumpr 243/257 Hydraulic Roller Cam and Lifter Kit for Ford 352-428

The COMP Cams CL33-602-11 Big Mutha' Thumpr is a hydraulic roller camshaft and lifter kit engineered for Ford FE big block engines (352–428 c.i., 1963–1977). Designed for serious street/strip builds, this cam delivers the aggressive, choppy idle and hard-hitting exhaust note that turns heads at every cruise night — without sacrificing broad-range power delivery.

The Thumpr series achieves its signature sound through a tightened lobe separation angle of 107°, which increases overlap between intake and exhaust events. Combined with an early exhaust valve opening and extended exhaust duration, the result is a powerful, unmistakable exhaust note paired with genuine horsepower and torque gains across the RPM range.

Camshaft Specifications:

• Duration at .050" Lift: 243° Intake / 257° Exhaust
• Valve Lift: 0.579" Intake / 0.563" Exhaust
• Lobe Separation Angle: 107°
• RPM Range: 2,500–6,200 RPM
• Cam Type: Hydraulic Roller (Retro-Fit)
• Camshaft Material: Cast Iron
• Camshaft Gear Attachment: 1-Bolt

Kit Includes:

• Hydraulic Roller Camshaft
• Hydraulic Roller Lifters
• Assembly Lube
• COMP Cams Decals
• Installation Instructions

Recommended Supporting Modifications: This grind is intended for street/strip performance builds requiring a minimum 9.5:1 compression ratio, 2,800+ RPM stall converter, performance intake manifold, rear-end gears, and headers. Expect a very rough idle characteristic of the Big Mutha' Thumpr profile.

Compatible with Ford FE engines including the 352, 360, 390, 406, 410, 427, and 428 cubic inch applications in non-factory roller block configurations.