4 Cylinder Exhaust Manifold to Head Gasket | Sierra 18-0680 Combination intake & exhaust manifold gasket fits GM 3.0L 4 cylinder marine engines with Vortec cylinder heads. Exhaust manifold gasket For GM 3.0L engines from approximately 1991 and up with Vortec cylinder heads All intake ports are of equal size and shape Will not work with all 3.0L engines - refer to engine model and serial for correct gasket Replaces Mercury 27-815528 Replaces OMC 3853256, 914578 Replaces Volvo Penta 3853256