Check to make sure your Fountain has 1.5 gears. I know they used 1.65's in a good amt of their boats. I forget which one's. Doh.

Your slip does sound high...but the speed sounds about right from what I've seen in reality vs. the magical test report that's difficult to duplicate in reality.

I have a flat bottom 32 with carbed hp500s with 1.5 bravos and spin stock 28p bravos 5000 rpm at 79.4. I'm also thinking you have 1.65 drives, but I'm no expert either.