Offenhauser air horn adapters are built for 4 7/32 in. carb neck, like the 1950's vintage 4GC, WCFB etc. Originally for early OHV V-8 conversion tight engine bays, these air horn adapters are a great fit for limited spaces. The air horn adapters' low-profile complements particular aesthetic setups and will also add a unique 'alien look' under the hood of your classic car.