COMP Cams CL33-601-11 Mutha' Thumpr Hydraulic Roller Cam And Lifter Kit Ford - 235/249 352-428

The COMP Cams CL33-601-11 Mutha' Thumpr is a retro-fit hydraulic roller camshaft and lifter kit engineered for Ford Big Block FE engines (352-428 c.i., 1963–1977). This kit delivers the classic muscle car idle sound enthusiasts crave — a distinctive choppy, thumping exhaust note — while producing strong horsepower gains and a broad torque curve across a 2,200 to 5,900 RPM power range.

Designed as a direct retro-fit for engines originally equipped with flat tappet camshafts, the Mutha' Thumpr profile steps up the aggression with early intake valve opening and long exhaust duration that creates optimum overlap for a powerful, hard-hitting exhaust note. The hydraulic roller design delivers a substantial power advantage over an equivalent hydraulic flat tappet grind while maintaining excellent reliability and ease of maintenance.

Key Specifications:

• Camshaft Type: Retro-Fit Hydraulic Roller
• Advertised Duration: 291° Intake / 311° Exhaust
• Duration at 0.050": 235° Intake / 249° Exhaust
• Valve Lift: 0.567" Intake / 0.551" Exhaust
• RPM Range: 2,200 – 5,900 RPM
• Application: Ford Big Block FE 352-428 c.i. (1963–1977), non-factory roller block

Recommended Supporting Modifications:

• Minimum 9:1 compression ratio
• 2,500+ RPM stall speed torque converter
• Performance intake manifold
• Rear-end gears
• Headers

Kit Includes:

• Mutha' Thumpr hydraulic roller camshaft
• Matched hydraulic roller lifters
• Assembly lube
• COMP Cams decals
• Installation instructions

The Mutha' Thumpr is the ideal choice for high-performance street and strip builds in classic Ford muscle cars and street rods where an aggressive idle character and serious power gains are the goal.