Performance Numbers for Yamaha Waverunner Jet Pump

I recently purchased a 1992 Yamaha Waverunner jet drive unit (WR500R) and I am going to attach it to an engine other than the one it was designed to go with. I am looking to see if anyone knows or has performance numbers for the original engine, such as RPM @ a certain Hp. I am trying to gear the new engine accordingly to match the jet drive and don't want to starve the jet drive with too high of an output RPM from the engine or not be able to achieve optimum performance with too slow of an RPM. Maybe someone could point me in the direction of finding these numbers.