Okay, after a bit more research, decided to throw a truck motor in ye old boat, after marinizing it of course, quick recap, froze the block and exhaust manifolds in my 1990-91 gm 4.3 omc. Had a couple options, thought about a complete repower, opted not to until my cobra outdrive fails if ever. This will be my first marine swap, so i figured I would post my progress over the next couple weeks so everyone has the chance to scathe me for using a truck motor, or maybe get some good sound advice from some curious onlookers. 
So, Im off to find a like year motor out of a truck, dont think it matters if its 2 or 4 wheel drive......(advice welcome)...., then I will begin the tedious process of parts matching E. manifolds...(hoping to find a decent aftermarket log style as mine are batwing).....then maybe a shift cable followed by an alignment tool, n maybe a few gasket sets, if I find any gaskets or bearings that need replacing after I remove the out drive...then a new shift interrupter as i would rather err on the side of caution.....n I guess a manual would be in order, (not sure which one).....maybe even a better place to start this process hehehe...so wish me luck, maybe a friendly word or two, and I will post some pics as we progress!
So, Im off to find a like year motor out of a truck, dont think it matters if its 2 or 4 wheel drive......(advice welcome)...., then I will begin the tedious process of parts matching E. manifolds...(hoping to find a decent aftermarket log style as mine are batwing).....then maybe a shift cable followed by an alignment tool, n maybe a few gasket sets, if I find any gaskets or bearings that need replacing after I remove the out drive...then a new shift interrupter as i would rather err on the side of caution.....n I guess a manual would be in order, (not sure which one).....maybe even a better place to start this process hehehe...so wish me luck, maybe a friendly word or two, and I will post some pics as we progress!