Sierra 18-1957-2 MerCruiser V8 GM 1981-2002 Exhaust Manifold - Replaces 807078T10 When in need of a Mercruiser manifold replacement, Wholesale Marine carries economical options to get you back on the water fast. Sierra has engineered a manifold replacement kit that includes the gaskets, spacers, and elbows so a complete manifold replacement can be installed quickly and easily. The unit is manufactured to be installed on either port or starboard engine block. Replacement manifold is designed for