The creation of the big 300+ motors are geared for the offshore boats Instead of running 3 200 hp they can run 2 300 hp and save alot in the weight and fuel department. The initial savings are huge having to buy 1 less motor to power the crafts. The new boats are leaning towards the outboard motors because running a set of twin 454 motors usually gets you about .75 mpg while the twin 300+ will double the number to 1.75mpg. Remember most of the time when you are running the big boats the cost of the fuel is nothing compared to the cost of the trip with bait , special equiptment, upkeep and docking being the most expensive part of ownership.
Art