White Pump Cam

The white pump cam for Holley 4500 carburetors is a precision replacement component engineered for carb tuning and restoration work. This accelerator pump cam controls fuel delivery during throttle acceleration, making it essential for anyone rebuilding or rejetting a Holley 4500 fuel delivery system. Mechanics and hot rodders rely on this OEM-style part to restore proper pump response and eliminate hesitation during hard acceleration.

Constructed from durable plastic, the white pump cam functions as a mechanical interface between the throttle linkage and the accelerator pump plunger. As the throttle blade opens, the cam profile forces the pump plunger downward, injecting a metered shot of fuel into the carburetor throat. This momentary fuel surge prevents the lean-out condition that occurs during rapid throttle transitions. The profile geometry of the cam directly affects pump stroke speed and total fuel volume delivered, influencing response characteristics and overall driveability. A worn or incorrect cam profile creates flat spots in acceleration or causes overfueling at cruise.

This kit includes a pair of cams, allowing complete replacement of both pump circuits in a dual-feed Holley 4500 carburetor setup. Restoration builders, bracket racers, and street rod enthusiasts benefit most from stocking this part during full carb rebuilds or when original components show wear or damage. Installation is straightforward—simply remove the old cam from the accelerator pump arm, slide the new one into place, and secure with the existing pin. Verify cam orientation and smooth pump operation before final carburetor assembly to ensure consistent fuel delivery across all throttle positions.