Carburetor Rebuild Kit for Holley 4011 Spread Bore 4 Barrel Carbs. This kit rebuilds all Holley 4011 spread bore carbs ( ask us if you are unsure of your application). This Walker Carburetor Rebuild Kit includes precision die-cut gaskets, needle and seat assemblies, accelerator pump diaphragms, power valve(s), idle screws, and all the miscellaneous small parts need for a fresh assembly.