So that would put it at about 8hp at 2400rpm, according to the curves. Coincidentally this is also the point of maximum torque. Perhaps that's not a coincidence after all??60% to 80% of max has seemed to apply to every diesel I've known anyway. Someone here may know an oddity about this one. But, you first have to insure your prop is properly pitched to allow you to get to max under load at wide open throttle for a few seconds. Otherwise, all bets are off. A quick google search says max rpm should be 3600.