I am dickering on a 47' Roamer (aluminum) that has a pair of 454(?) Gas engines (original??). I have available to me a pair of Ford 275 HP Diesels with transmissions and a pair of 471 Detroits without transmissions. Both are fairly cheap. Both are used but in good condition and I trust the sellers as they are both good friends. Which of the THREE engine pairs is the best for powering a 47' Roamer? The gas engines are in the boat and run fine. BUT....they are gasoline.... I would feel better with diesels.