What speeds can be expected in a 24 with 650 hp

Difficult to say. Dont know much about your boat and set up.
Im at 76 with 30 years of bottom paint, heavy boat, merc 525, its, bravo xr, bravo 1 26 pitch propp.
Going for 80 next summer.

Motor rigged and built by mrd 511ci tall deck 530 hp bravo 1 24 cupped to a 25 running around 5600, 5700 rpm around 80 82 mph

Is this your expectation or is this real nrs?

Not an expectation this is my set up now that I am replacing

Aha, cool.
So what nrs are you hoping for?

Motor supposed to be good for 5600- 5700 rpm probably going to run a bravo1 Prop not sure what size yet

I got a 24 with a single 250 merc outboard running 62, I'm in the process of re-rigging with twin 300's and I'm hoping to get low 80's

That sounds like a great upgrade let us know whatyour gains are I think you are going to be pretty suprised! Let's hear what air dog has to say what your increases will be he seems to be the expert with the outboards and how to set them up and could prob give you some input

I am hoping for a surprise,I expected the boat to be faster than 62 with the single merc