"The carb can add HP by compar
"The carb can add HP by comparison if a lot more air can flow through it than the one being compared to, but even that would reach a limit since the motor and exhaust flow isn't unlimited. Same goes with an EFI system- if the throttle body is replaced by one with a larger orifice, more air will pass and power will increase. A motor is basically an air pump. Most of the differences come from roller lifters/rockers, high flow intake manifolds, different heads with larger valves, etc. Until the '07 model year, marine EFI systems haven't used a catalytic converter or 02 sensor, so the fuel mapping is able to be changed so it's about as rich as you would want, if you have access to the software to change the programming. Changing from a 2BBL to a 4BBL will add HP, OTOH. Better performance from EFI, I won't argue about.
Coolbreeze- if you look around in marine salvage operations, you may be able to find a motor or EFI system from a blown/cracked motor and drop it on if it's from the same size as yours. The program for a 5.0L isn't the same as a 4.3L, 5.7L, or any other motor. Buying the parts from V-P is possible, but it would be pretty expensive. Buying an aftermarket system (Holley, Edelbrock, etc) is still a possibility, though."
