First let me state that I truely don't plan to do anything along these lines for several years (realistically I would say 4-5 years out). The curreny power only has 250 hrs and that is after I put 100hrs on last season. I plan to use it and enjoy until the current power gets tired and I am hoping technology continues to gravitate towards the diesel option. I do appreciate your input as far as determining if what I want to do is attainable and what sort of a price tag the project would have on it. I certainly don't want anyone to put too much time into the numbers expecting me to do something in the next 12 months. Joe, regardless of where this thread goes, I will definately contact you personally when I am ready to pull the trigger on the project.
As far as numbers are concerned minimum planing speed without tab input is right about 2400rpms depending on air temperature (rpms run about 100 higher if it is cool and dry). Speed at that RPM is right about 31 mph on a hand held gps. I am running stock 502 mag mpi's that currently have 250hrs. They are supposed to be 415 hp at the prop and I am currently spinning non labbed 4 blade 24 pitch bravo 1's. Regular bravo 1's with 1:5 ratio.
The best I have seen for top end was 67.1mph on a handheld gps at 4980 Rpms. That was light on fuel (200 gallon tank) with me, my wife and our two year old. Temp was in the mid 60's with slight wind chop. It will do 65mph any day but I rarely run it above 60mph. With a small child it is sort of like having a caddy that will cruise beautifully through the snottiest water at 45-55mph all day long.
Most of our running is between 3,000 and 4,000 rpms which at 3,000 rpms is about 38 mph and 4,000 is closer to 55mph if neutral on tabs with slight trim.
Hopefully this helps and I appreciate the info on what is possible with the old resin bucket.