Can I use an automotive longblock or shortblock to replace my Mercury Racing engine?
No, an automotive block cannot be used for several important reasons. The Mercury Racing ECMs (electronic control modules) are specifically calibrated to each of our engine models. It would not be possible to determine the effect on the performance or compatibility with an automotive engine. In addition, automotive engines are not equipped to endure the high rpm duty cycles and harsh environment that marine engines see. Further, some of our engine components are unique to marine engines, such as the welch plugs, camshafts, cylinder heads, head gaskets and pistons.