Mercury - Quicksilver Manifold Gasket Set For V8 MerCruiser 350 Mag, 5.0L & 5.7L/LX Engines 807473A1. Overview. Keep your MerCruiser's exhaust system sealed and running efficiently with the Mercury Marine 807473A1 Quicksilver Manifold Gasket Set. Designed specifically for V8 MerCruiser 350 Mag, 5.0L, and 5.7L/LX (Gen+) sterndrive and inboard engines made by General Motors (1996 and newer), this OEM three-piece set provides a perfect seal between your manifold and cylinder head. A tight seal mean