Mercury - Exhaust Manifold Gasket Engine Sealing Series Composite Marine Gasket 8M0162487. Overview. Running a big-block MerCruiser has its own kind of music - that deep, steady rumble you feel more than you hear. But anyone who's owned one knows that sound only stays strong when the small things are taken care of. An exhaust manifold gasket may not look impressive, but it's one of those parts that quietly keeps everything working in harmony. Mercury Marine part 8M0162487 brings back that sense