Unfortunately I didn't get to run the boat to much with the whipple motor. I had it out once in Havasu right after we got the boat together. We were just taking it easy trying to get everything dialed in. It ran 105 at 5400 rpm. I was on it hard coming up to the gorge and the drive let go at a little over 100. After all the work to get the boat together I only got to drive it for about an hour and a half. I guess I had it coming for buying a used drive.
I brought the boat back to the shop and rebuilt the drive. While waiting for parts and trying to find time to work on my personal stuff the opportunity came up to sell the motor and step up. I was thinking about it last night and realized since I've owned the boat it has been to the lake a total of five times with three different motors.
To answer your question a little more directly, the boat ran great with this setup. For the budget minded boater it is really the best way to go fast. A well built drive will last for a while at this power level and the motor is not a ticking time bomb. The boat was fast enough and should have easily ran 115. It was also kind of cool having mufflers and a flat engine hatch most people thought it had a 496 or 525. I loved them not knowing and then seeing their face when I opened the hatch.