Mercury - Exhaust Manifold Gasket V12 Verado & SeaPro Series Composite Seal 8M0177479. Overview. Anyone who's spent long days offshore knows how much your confidence depends on the small, unseen parts inside your engine. The big V12 outboards are impressive on their own, but they only stay that smooth and powerful when every seal is doing its job. The Mercury 8M0177479 Exhaust Manifold Gasket is one of those pieces you never think about until you need it - and when you do, you'll want the kind t