Miller Killer you are way off base with the dyno ASSumption. The dyno is your friend. You are not putting any more stress on a motor on the dyno than just running it in your boat. The dyno is used to to break in and tune your motor to where it will see most of it's running time. Ideally, you will make pulls on the dyno in the range of where the motor will make it's peak torque. In most jetboats you will run your Wiz Bang impellers and shoes and nozzles etc and the motor will pull to 6000 rpm maybe. By using the dyno you can adjust and move the power band around to accomodate that without beating your shit up at the river. You may find out that your cam is wrong or your motor is not happy where the timing is. When you come off the dyno you will, at most, need to make one jet change if that. You will spend $500-$700 to run on the dyno but it will be the best money you ever spent. Why do you think the guys taht race are always on the dyno. Because it shows them where they are lacking and where they are making power. It isn't just for racing.