Well sort of it the real answer. Usually not a "car" engine, but a "truck" engine would be closer to the answer. When companies wanted to cheap out, I have seen 2 bolt main with a cast crank, that would be a normal "car" engine. A 4 bolt main should be a "must" have for a boat. If you want it better, balance the rotating assembly and you have a better chance at "bullet Proof" as you can get.
You can get a Autozone or whatever truck crate motor and that will work just fine, but your warranty is no good from what I have seen if it's in a boat.
Now, there were and still are some parts that are "marine" only. Some of the intake manifolds were, in fact some racing applications with carbs prefer them and will order them new vs a car one. Different plane and flows better to the front ports.
An Edelbrock or other is still way better though.
Cam selection is probably the biggest thing. You only have 100's to choose from with small and big blocks.
