Holley 20-20

The Holley Dominator 4500 Secondary Linkage pump cams are designed to tailor your Model 4500 or 4500 HP Dominator carburetor's secondary throttle input to suit your needs.

The Progressive linkages available in "Soft" or "Standard" allow you to run on the primary side of the carburetor for idling or low speed part throttle cruising and also work well on dual carb arrangements.

The 1:1 ratio linkage is used primarily on single carb race only applications where both primary and secondary opening is desired proportionally at the same time.