Wow, thats a project, The good thing is MC Hulls are pretty solid. I spent last winter agonizing through the whole dilemma of what am I gonna do with a saltwater motor, for my 209
. it came with an Indmar LTR, unfortunately Indmar no longer makes the intake manifold, which made it impossible to reuse the fuel injection system which forced me to find a new solution that didn't require a new engine, fuel injection and gauge package. I got lucky and found a similar year donor boat with 200hrs and was able to just drop a donor motor and transmission in. I am extremely pleased with the supposed downgrade of going from the LTR to the 310hp Predator TBI motor.
I'd avoid michigan motors, check into Barr Marine, Florida Inboards, or start calling local marinas, and machine shops. You might get lucky.
The only argument that justifies a 10k repower is that the fuel injection will work with Zero Off speed control. And you still have to spend more $$$ to get the gauges to all play nicely.
I'd entertain the idea of buying a vortec chevy motor, have it overhauled and either put a carb on it, or buy an aftermarket fuel injection. Go buy a hot rod or car craft magazine and search through the ads, there are a ton of tuneable options. Some people might hemorrhage ar the idea of a non marine fuel injection due to fire issues. My feelings is I know my boat inside and out since I tore it down and put it back together. Before I turn the key, I lift the cover check the bilge,pull the dipsticks, check the oil levels and smell for fuel.
Your'e going to feel overwhelmed quite often, but there are numerous resources out there to get you through the problems you'll encounter. Just keep at it and when in doubt move onto another part that you know you can make progress on.