The GM base marine engines that Michigan Motorz offers are the EXACT engines that MerCruiser, Volvo Penta, Malibu, Marine Power, Crusader, Indmar, etc., purchase directly from GM Marine Powertrain.
Genuine base marine engines are marinized by GM Marine Powertrain and frequently include the marine oil pan, valve covers, circulation pump, harmonic balancer, cylinder heads and all internal parts, including marine specific parts. OEM's (MerCruiser, Volvo Penta, Marine Power, etc.) purchase these engines from GM and install their own unique accessories (such as exhaust manifolds, ignition systems, etc.), thereby creating their own private label marine engine.