Quick and Easy Installation Diecast Aluminum Adapters Includes Gaskets and Studs Including Nuts and Washers Reference:1933 Carburetor Flange (application): Square bore Carburetor Bolt Pattern: 4-bolt (5 5/8 in. x 5 1/8 in.) Manifold Mounting Flange: Large 2-barrel Manifold Bolt Pattern: 4-bolt (3 3/4 in. x 2 in.) Carburetor Flange (application): Square bore Carburetor Bolt Pattern: 4-bolt (5 5/8 in. x 5 1/8 in.) Manifold Mounting Flange: Small 2-barrel Manifold Bolt Pattern: 4-bolt (3 1/4 in. x 1 7/8 in.) .