If a given boat runs 75 mph at 5500 rpm with around 645 hp (motor probably makes around 600-620 hp @ 5500) spinning a Berk A impeller, how much power will it take to make it run 100?
According to Jerry Friddell's Jet Boat Performance Calculator you would need 880 HP spinning the A impeller at 6538 rpm.
The calculator used to be available for free download at liquidaddiction.net, but the site is apparently gone.