Re: Repower
I figure this would gain me horsepower, mileage and much needed deck space(every inch counts).
Power-wise, a supercharged 4.3 would be the equivalent of the stroked 350 (383) recommended by Bondo. With the supercharger, you'll get higher cylinder pressures, more critical mixture ratios (easier to run lean when the gas craps out after sitting in the tank for a while or gets water in it), higher valve temps, higher loads on all the recipricating parts, and much more heat to try to get rid of. You'll quickly discover that cubic inches are your best friend if you're trying to make power in a boat.
As far as mileage, gasoline provides about 11 HP per gallon per hour. If it takes 110 HP to run your boat at the speed you desire, any engine you put in it is going to require about 10 gallons per hour whether it's big, little, supercharged, whatever.
Maybe it's worth it if 3 inches of deck space is that critical to you (I'd just get a bigger boat).
The supercharger would be a good way to go if you like spending money on motors and want to say your boat is supercharged.