Sierra 18-4349 Exhaust Manifold Gasket Set The Sierra 18-4349 Exhaust Manifold Gasket Set is interchangeable with the following: GLM 39880, Mallory 9-61455. Contains: (2) 18-0872 Exhaust Manifold Gasket, (2) 18-0897 Exhaust Elbow Gasket. Each Sierra product meets or exceeds the original equipment part it replaces. Sierra Exhaust Manifold Gasket Contains: (2) 18-0872 Exhaust Manifold Gasket, (2) 18-0897 Exhaust Elbow Gasket Sierra part number: 18-4349 Interchangeable with the following: GLM 39880, Mallory 9-61455