Alternator conversion may require this kit.This is a adapter plate to allow a stock carb setup to be run with an alternator conversion kit. Bolt spacing is 2-1/8 and is 1 thick Carburetor: Solex/Brosol 28 30 Thickness: 1 Bolt Spacing: 2-1/8 SOLEX 28 & 30 CARB SPACER