heres the scoop, first off this is my first jet boat, been into skis and regular outdrive boats. familiar with engine and mechanics etc. I picked up a 77 tahiti mini cruiser 19' over the winter, tore it completely down and spent all winter building her from scratch. set it up with a 460 ford making aprox 600hp. took her out for the first time and got her running clean and smooth. it has a jacuzzi wj/b with place diverter, was told the boat ran good when it was last in the water in 01 when the guy loaded a ton of nitrous and blew it up and just let it sit. took her out for second time today and it was running perfectly except I'm turning 5k rpm at 45mph gps. from the research i have been doing this doesn't seem right for a motor making around 600hp. motor is fresh rebuild, stock crank/stroke, keith black pistons, eagle rods, scorpion roller rockers, comp cam kit (matched for b impeller), cobra jet heads ported, all new head components, high volume oil pump, crane fireball box, malory dis, 850 holley with cut choke and 80's currently, everything port matched, etc. good solid build with aprox number from machinist. I'm very disappointed needles to say, i was expecting somewhere around 60mph. I'm thinking the weak spot may lie in the pump or there is a different impeller in the boat then the pump tag says. I'm familiar with the slip feeling or caviation on a jetski, but maybe its different in this circumstance? the boat gets up and goes if you hammer it from a dig (doesnt feel like seaweed) but it takes a while, doesn't quite pull hard or jump but also doesn't sound like its caviating. if I'm up on plane with trim about neutral the boat has quick response if letting off and re-applying throttle quickly. from about 4k to 5k it doesn't seem like i gain much mph for a 1k rpm change. before i put the engine in i did a quick check over and the pump was free and smooth with really no play, so i figured there was no major issue. couldn't really get a good look at wear ring due to i was only looking through the access hole in the top and saw the impeller had a outer ring on the blades (different from jetski). looking for an opinion of what you guys think. problem with driveline, or do i have an expensive paper weight of an engine?
thanks a lot!