Carburetor hat designed around performing a tune-up or reading spark plugs. Should work with any 4150 4 barrel carb. The opening is for the standard 5" air cleaner flange carb and will not work with non flanged 2 barrels, or 4500 ("Dominator") carbs that have 5.5-7" air cleaner flanges.

One rectangular slot for a wrench, two rounded slots for wrenches or ratchets, and a pocket for a 5/8" spark plug socket. 8 holes for spark plugs.