Housing Thermostat for Mercruiser GM Big Block V8 90736A18

Lower Thermostat Housing That Is used On Mercruiser Big Block Engines With Raw Water Cooling and Center Rise Exhaust Manifolds. It Fits The Mercruiser 454/502 Mark IV & Gen V Engines. Note that the mounting holes are not directly across from each other, one is slightly ahead of the other. If your holes are directly across from each other see part number GLM13230 This Item Replaces O.E.M. # 90736A18.