replacement 262(4.3) ci engine

hopefully someone can help me with this. i was given a 1986 I/O 17ft searay which had a 4.3 v6. the boat is beautiful almost perfect condition except for the fact that the engine was removed due to a cracked block. i am in the process of trying to get a hold of the old engine and i currently have access to a 4.3 vortec from a truck. i am an auto mechanic by trade and two years of schooling. but have never played with an I/O marine engine before. all my past boats were O/B. my question is can i use the marine engine parts and the truck engine block to build a decent marine engine? i only use my boats in freshwater and never travel more than 5-10 miles away from the launch area(we have small lakes here in upstate ny). and also im wondering if the vortec multiport fuel injection can be used instead of a marine carb. im fully aware of having to use the origional computer and wire harness from the truck and modifying it which is no problem for me to do. i have done it when converting older carbed cars with fuel injection. so i guess what my main question is can i just trade blocks? any help would be appreciated!.......oh and i also plan on putting new piston rings and bearings in the truck engine.

 

I've a 4.3 in a runabout (2006 Caravelle). Perhaps some of the more senior members will post as well. To my knowledge the blocks should be interchangable. I do know that some of the larger v8's that come from companies like Crusader are equipped with 4 bolt main blocks, but I can't believe that this would be an issue with a v6.

When I did my first oil change on my 4.3 I found an AC oil filter. The filter was half black from the paint that Merc used on the engine. Behind the filter, where the black paint couldn't reach was the light blue factory paint from GM. That leads me to the conclusion that the block is purchased from GM and then "marinized".

I can't see why engine mounts, manifolds, etc. should not just swap over. You'd want to use parts USCG approved for marine use of course. I'd take a good long look at the exhaust manifolds. They are likely original and at what? 23 years old they have probably reached the end of their service life.

I'd check on the EFI though as I'm a carb guy and not experienced in that area.

Good Luck,

MIA