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Comp Cams Part Number 12-602-4 is a Big Mutha' Thumpr hydraulic flat tappet camshaft engineered for Chevrolet Small Block 262–400 engines (1958–1998). Designed for aggressive street/strip performance, this camshaft delivers a very rough idle and requires supporting modifications including 9.5:1 compression, 2800+ stall converter, performance intake, gears, and headers.
Big Mutha' Thumpr series for an extremely aggressive idle
Hydraulic flat tappet camshaft
Designed for Chevrolet Small Block 262–400 (1958–1998)
Optimized for a 2,500–6,400 RPM operating range
Requires 9.5:1 compression and supporting drivetrain/exhaust modifications
Street/strip performance focus
3-bolt camshaft gear attachment
| Specification | Value |
|---|---|
| Camshaft Type | Hydraulic Flat Tappet |
| Series | Thumpr |
| Engine Family | Chevrolet 262–400 c.i. (1958–1998) |
| RPM Range | 2,500–6,400 |
| Advertised Duration (Int/Exh) | 295 / 313 |
| Duration @ .050" (Int/Exh) | 243 / 257 |
| Valve Lift (Int/Exh) | 0.500 / 0.486 |
| Lobe Separation Angle | 107° |
| Intake Open (BTDC) | 44° |
| Intake Close (ABDC) | 71° |
| Exhaust Open (BBDC) | 84° |
| Exhaust Close (ATDC) | 49° |
| Valve Timing @ .006" | Not specified |
| Gear Attachment | 3-Bolt |
| Usage | Street/Strip |
| Lifter Type | Hydraulic Flat Tappet |
| Warranty | 12 Months |
| UPC | 036584175278 |
| Emissions Code | Not specified |
| California Proposition 65 | Cancer and Reproductive Harm (P65Warnings.ca.gov) |
Make: Chevrolet
Engine Family: 262–400 c.i. Small Block V8
Model Years: 1958–1998
Cam Gear Style: 3-bolt
