Your goin to need 100-150 hp to get those gains. I have found on that size boat a 10mph increase neads about 100hp more.
Thanks all for the replies. I am going to try and get over to the boat this weekend, and see what I can figure out. I am kinda tempted to sell it now while I'll only lose a fraction of my ass, and go a little bigger. Hopefully that urge passes soon, but thats doubtful.