There are (4) Boosters with the stamping (1) and (4) Boosters with the stamping (2), the single one in the picture is a 1 as well, just stamped different.
Holley Dominator Carburetor Rebuilder Venturi Booster Pins Progressive Linkage
Holley dominator carburetor carb spacer Ford, Chevy, Dodge, chrysler 454 427 540
4500 HOLLEY DOMINATOR CARBURETOR TO 4150 MANIFOLD ADAPTOR, 1" HIGH,CARBY SPACER
(2) Air Cleaner Gasket Air Horn 7 1/4" ID Fits: Holley Dominator Carburetor 4500
Holley 0-80688 1050 CFM Holley Dominator SP Carburetor
0-80689 Holley Holley Dominator SP Carburetor
