OEM gasket seals between the valve cover and cylinder head on Crusader Mark IV 454 and 502 cu. in. marine engines. GM Big Block Valve Cover Gasket | Crusader RM0194 For GM Mark IV 7.4L 454 and 8.2L 502 big block marine engines Sold separately - 2 needed per engine High quality silicone rubber gasket with a metal core Original Crusader Replaces Crusader 30000, 30222, 33558 Replaces Mercury/Mercruiser 27-14765 Replaces Pleasurecraft Marine RM0194