Re: Car engine for outboard
I suppose it could be done, but why bother? Problems with tipping an automotive engine to a vertical position would include the oil system, since you couldn't use a standard oil pan and oil pickup from the pump. If it was carbureted, you'd be in big trouble, since a vertical engine needs a side-draft carb.
Still, I wouldn't be at all surprised if some of the V6 and V8 outboards use engine blocks from one japanese auto engine or another. Nissan, Suzuki, whatever. But that's where the similarity would probably end.
Of course, I/O units almost all use auto engine blocks as their starting point.