1963 GMC 3500 Engine: 4.8L L6; 1 Bore Gasket; Position: Carburetor To Intake Manifold;. 1963 GMC 3500 Engine: 4.8L L6; 4 -Notch Bypass; 1 Bore Gasket; Position: Carburetor To Governor;. 1964 GMC 3500 Engine: 4.8L L6; 1 Bore Gasket; Position: Carburetor To Intake Manifold;.
