Fits both stock Mercruiser pump and Jabsco aftermarket pump. Gasket included. Composite aluminum, plastic, and cast iron construction of original Mercruiser water pumps does not hold up in marine environments. Now you have the choice to replace the complete pump assembly, the end cover only, or the impeller with a more durable, longer lasting pump. The Jabsco Mercruiser-type replacement pump has a one-piece bronze body and bronze end-plate with a replaceable cam and wear-plate so it can be rebuilt when needed.