Rebuild Kit for Holley 4150 4 Barrel Double Pumper Carburetors. Cross reference to Holley 3-485 rebuild kit. Walker Carburetor Rebuild Kits include precision die-cut gaskets (non-stick on Holley style kits), needle and seat assemblies, accelerator pump diaphragms, power valve(s), idle screws, and all the miscellaneous small parts need for a fresh assembly.