The Vortec V8 Marine engine started in 1998 and can be identified by having 8 total intake bolts holding the intake manifold to the cylinder heads. The bolts go straight down instead of at an angle like all previous V8 Engines. The engine also has an unfinished fuel pump boss which means it must use an electric fuel pump. The Vortec design relates to cylinder heads having a much improved air flow along with a Roller Camshaft which gives the motor more horsepower.
This engine is a direct replacement for all MARINE engines 1998 and newer. This is the engine as it comes from General Motors to all of the marine engine manufacturers such as Mercruiser, OMC, Volvo, Crusader, Indmar, and Marine Power, so rest assured you are getting a true MARINE ENGINE with a MARINE ENGINE WARRANTY and not an engine someone has tried to convert using inferior parts and pawning it off as a MARINE ENGINE.