Merc 565s are equivalent to 600hp aftermarket Dyno standards

I fully understand that, when you dyno a merc engine at j607 you see #s 3.9% higher. I also know a maximus acts like a taller prop, thats why i mentioned it. To me it would be like trying to turn 34 pitch props. I tried a 28 maximus on my Baja once, it ran almost 90 mph w 1.5 gears before it sheared off the prop shaft, i would think if you could spin 32 maximus props at their 8%prop slip i would think youd be going over a 100, i havent looked at a prop slip calulator though

So running the numbers thru the prop slip calculator tells me at 10% slip at 5400 boat would be going 98mph so either the props would have to be cut down and labbed quite a bit to get slip way up or engine would never hit its peak rpms unless boat ran close to 100 mph, are the new active thunders really fast hulls, could it run those numbers w 600 hp?

Idk. The OL 36 could run almost 100 with 565s. The latest 39 velocity could too.

Set your throttles at 3000 rpm, and start playing with drive trim, starting at neutral.
Watch the decimals on your GPS speedo. I think you will find that boat to be the fastest at neutral trim or slightly above.