motor advice

[shawnb1977]

i have a 1987 27 foot sport craft fisherman, that has twin 3.7 mercruisers io, looking for a upgrade , has to be a straight 4 because of space

[branhamautomotive]

Unfortunately I don't think any thing else swaps with those motors. There is not anything larger in displacement than those in a 4 cyl. I know I have seen those motors be upgraded with 4bbl carbs and even turbos to get more power. It's a we'd little motor having basic s 460 ford head but a bottom end more like a gm. That being said I don't know for sure if the head us exactly the same as a 460 but I know it's really close. But 460 had terrible exhaust ports, maybe if close enough and seeing it has its own closed loop cooling maybe a new aluminum 460 head would help the hp and not be exposed to direct cold lake water