GM V6 Exhaust Manifold to Head Gasket | Sierra 18-2909 Gasket seals exhaust manifold to cylinder head on GM 3.8L & 4.3L CID marine engines. Exhaust manifold gasket For GM V6 229 and 262 cu. in. marine engines Replaces Crusader 97498 Replaces Mercruiser 27-99757 Replaces OMC 910157, 915025, 3853412 Replaces Volvo Penta 856116, 3853412 Replaces Yanmar YSC-12190-00-0C, YSC-12190-00-AC Replaces Mallory 9-61421