Chevrolet Performance 12363407 - CNC-Port-Matched Intake Manifold for BBC Oval-Port, square bore, Holley Carburetors

Same as P/N 12363406, except it has been CNC-port-matched for GM aluminum oval-port heads with large oval-port heads (1975-and-older), and all aluminum heads with oval-ports. NOTE: Open carburetor spacer is not recommended with use of dual-plane manifolds.