That you, Doonut? recognized the avatar...

I have a couple of opinions. Some may be valid, some not.
1. Sorry, but I don't think you will ever see 6-7% slip, especially with that hull. I would shoot for 8-10%.
2. Unless you have dyno sheets, I seriously doubt 600hp out of a 454. Next to impossible unless you have spent 10's of thousands per motor. You will be lucky to have 500hp a side. I have decently built motors with good cams, etc, AND B&M 250 blowers and am only at 600hp. My speed mid 70's.
3. Good news is you should see low 80's with 500hp a side. Need to work on tuning and props. I would go to BBlades.

I'll chime in the same as Hollowpoint...


Need more info on your engine combo. A worked up 454 with a .570 lift cam doesn't say much about it. I can tell you from my own experiences that you would need some "not so boat friendly" compression, and aftermarket heads to get that number out of a 454. Serious RPM, too.

Can you provide some more information? Have you had the boat in the water for testing?