carb adapter 4bbl to 4bbl Any 4bbl carb. to any 4bbl manifold except Holley 4500 and OEM manifolds with exposed exhaust crossover tube. Measures 3/4" nominal height of the adapter only, w/o gaskets. Included in this kit are the gaskets, studs, nuts and washers. This easy to install adapter is made of diecast aluminum.