Can you swap a car engine into a boat?

[Frank]

My buddy was given a 95 VIP boat that has a 4.3 Mercruiser (Chevy 4.3 V6). The engine seems to be locked up. Pulled the plugs and they were rusty. This boat isn't worth dumping a lot of coin or time on. Instead of trying to free it up, we were wondering about finding a Chevy 4.3 out of a junkyard from a pickup and put in it. Are the marine cams that much different that would make this a bad idea? I have no ideas the difference in a vehicle cam and a marine cam.

[71chevellejohn]

I know there are some marine engines that run backwards from the land counterparts. Not all but some.

[Cooter]

marine applications don't lug around at low RPM like automotive applications. I would recommend getting a marine cam for it

[LANTIRN]

I've seen a V8 put into a boat before. I think it was an old carbureted chevy 350; about the only thing I remember for certain is it was carbureted, though I know that does not help you much. Not sure what all he had to do to get it in the boat and working properly, but the boat did float and move under it's own power, so it is possible, though I don't know what it cost him in time and money to get it finished.

[Frank]

I've seen a V8 put into a boat before. I think it was an old carbureted chevy 350; about the only thing I remember for certain is it was carbureted, though I know that does not help you much. Not sure what all he had to do to get it in the boat and working properly, but the boat did float and move under it's own power, so it is possible, though I don't know what it cost him in time and money to get it finished.

In our case I'm just talking a swap like for like since it already has a 4.3 Chevy, but sounds like there might be directional rotation and cam issues that make it not worth it. We'll probably pour some diesel in the cylinders and just let it sit why gently rocking the crank back and forth every now and then to see if it starts to move.

[psdtech]

motor mount bosses on some of the marine blocks where different (at least the last one i saw)

[JimD]

Did it, my celebrity has a 4.3 ltr short block in it. Been a few years since i did the swap. Wasn't really straight forward tho. Problem 1 was the crank/flexplate size, only 4.3 car engines that had the correct size/bolt spacing was from 1985-86 impala's and caprice. Next up was the exhaust manifolds physically bolting up to the heads, the shape of them hit the top corner/ & valve cover. What i did was yank the heads and put the old 3.8 heads back on, nothing wrong with them, the 3.8 block was cracked.

[Grimpala]

I've got a fully dressed 4.3 if you want to try this. $500 and it's yours, hell, I'll even deliver it in the metroplex

[smokey3550]

If you want a v8 swap you'll need the wet (water cooled) exhaust system for the motor, 305 or 350 would be about your only choice. Stock cam will work. Auto performance cams dont work in boats with wet exhaust manifolds. You need either a stock cam or performance marine cam. Your 4.3 would be standard rotation.

[mikeb]

Many, many years ago i did this swap into a friends boat. They had bought the boat at the fall boat show and forgot to drain the block for the winter. Needless to say, next spring it leaked like a sieve. We found a 4.3 out of a car that had caught fire, and reused the exhaust manifolds and rotating assy from the original boat engine. The block and heads were from the car engine.

I also bought a marine cam from chevy and installed it. It all worked out fine, and it had lots more power than the original boat 4.3 did.