Mercury - Quicksilver Head Gasket Engine Seal V8 MerCruiser & GM Inboard 75611001. Overview. A solid head gasket keeps your engine's compression strong and fluids where they belong. The Mercury Marine 75611001 Quicksilver Head Gasket is built for V8 MerCruiser sterndrive and inboard engines made by General Motors, including the 283, 305, 327, 350, and 377 CID blocks. It also fits certain OMC inboard and sterndrive engines of the same size. Crafted to Mercury's original specifications, it provide