I think I'm gone track down a pair and just swap them, keep the boat I like and know what I have. Alot cheaper than new boat I guess.

PM "BoatDoctor". He owns a 312 with ''whipple" charged 7.4 MPI's. He see's 87+ MPH (GPS) everyday. Though IMO, you would need to freshen up the heads before installing superchargers.

Any idea how to reach him i tried sending pm and it won't go through as he does not execpt them.

Check your PM box for his contact information.

Need to freshen up more than the heads. Lowers in that set up, if not upgraded, will be toast in no time.

Speed Calculator
 

Here is a speed calculator app that will help you see what extra power will give you. Meant to post this the other day, but did not have the link. Be honest with the numbers you plug in and the estimates are pretty close.

http://www.go-fast.com/boat_speed_predictions.htm

Ditto on needing new drives/props if you go to big power - don't forget about steering upgrades as well. K-planes are a must at high speeds IMHO. Assuming you have bravo ones, they won't last long behind big power.

rubadub, that speed caculator seems to be right on, good info. My 312 has 502's with wipples and imco lowers, 29 pitch props 98.7 mph gps