Yoeman I would start by measuring your doors and then the engines. That will dictate much of your plan going forward from there. Tearing down in the boat may be needed to get the clearance needed and that makes things lighter too.
While in the engine room measuring look at the structure of the cabin sole to see if you need to block it up to support a homemade lifting frame inside your cabin. If you can build a stout lifting frame the rest comes pretty intuitively as far as chain fall, come-a-long etc.
Good luck with your project.
Btw, skateboards are good for more than keeping your kids busy when its time to move that 350 across the floor.