Sierra 18-4389 Mercruiser Intake Manifold Gasket SetSierra high-quality engine parts are designed to meet OEM specifications. Fits MCM GM In-Line 6 cyl.; Interchangeable with: GLM; 39660; Mallory; 9-61212; Mercruiser Stern Drive; 27-47453A1; Application:Mercruiser Stern Drive 165 GM 250 I/L6; 1970-1978; 2770032 thru 5178958; 165 GM 250 I/L6; 1979-1981; 5178959 & up;