I don't know about the 4cyl to v6 conversion, but i will say that if you can get that boat for about $200-300 then its worth it, otherwise run away. I bought a boat that needed a motor and i had 1k just in getting that done (did the labor myself), and you will have to do an outdrive on top of that which will probably be another grand for one in decent shape. then you will be left with a 1992 boat that you have $2500 wrapped up in and you will never get that money back out of it.