The boat in an 89 TG with notch transom, is 575-600 hp enough power to spin 28 4 blades to 5000-5200 ?

kinda what I was thinking, It has 23's on it now and reving to 6k+, maybe a mirage 25 + 3 blade ? engines are 580's dart intakes and 1100 dom's

1. is it going high 70s

He's not sure no speedo working in the boat, Id guess 68-72 but just a guess, I'm just trying to get the rev's down and pick up a little speed

Thanks, I asked him to down load a gps speedo app on his phone and give me some numbers next time he's out............I'm thinking his boat is around 10K

A 38 Flatdeck will be around 11k dry. It will depend on the hp/torque curve of the engines as to how to prop it.
I would say to try going up 2-3 inches in pitch to start. I doubt he would be able spin the 28 Bravos to 5000rpm.

Top gun will weigh around 9800-10,000 with light to no fuel, what drives?

That HP with TRS?? your looking at worked 25 Mirage plus or 24 Hydromotives spinning 54-5600 range, or a 24-26 Bravo around 5200 speed should be 74-77 ish depending on actual HP it has and conditions.

If Konrad boat with 600 HP a 26 Bravo1 will spin 5200@ 73 mph or close to it. or a 28 to 5000rpm at 71mph

Its been awhile but i seem to remember my 525sc's, trs, 26p bravo @ about 4900rpm, 71 or 72 mph using gps phone app.