Re-powering question
 

I'm looking at buying a boat that had Volvo 8.1L engines and volvo drives. The engines and drives were pulled leaving the gimbals and exhaust. This boat is a 2000 and I'm guessing it would be best to put volvo drives back on but not sure about the engines. If I go with mercruisers or something else will there be significant changes and modifications required? What about stepping up to diesels? the boat is a 40ft sport cruiser. Any thoughts on the most cost effective way to get this boat together?