"Ted" wrote in message
...
Is anyone familiar with the challenges or benefits of replacing a
typical diesel marine engine with a stern drive engine?

I have an older, 40 foot wood boat with a single prop Detroit Diesel
6-71 that is located approximately midship. To create more room below
decks and add the security of having two engines, I am considering
removing the old engine and installing two stern drive engines near
the bow, just below the cockpit

..

I assume you meant installing the engines near the stern, not the bow.

Regardless, a boat is designed (or should be) with a specific weight
distribution that affects the center of buoyancy, and other sea handling
issues. I know of gas to diesel retrofits in originally well designed
boats that totally screwed up the boat.

I'd look into this project carefully.

Eisboch