500 efi converted to a 540 cu in. JE blower pistons, dart pro 1 aluminum heads, 632" cam. 60 lbs injectors, M1sc procharger at 5 lbs boost.
XR ITS drive with imco shorty, 1.36 gears.

engine will pull 4800 RPM with a labbed 32p bravo 1 4 blade to 95 MPH. back of boat gets sooty.
a 28p just touches the 5600 rpm limiter at 101 mph.

First question: does it seem I should have more HP with those upgrades on motor,"baught the boat as is with a reciept listing those parts"
2nd question: prop suggestions?
3rd question: should I up the boost?

Your touch the rev limit with the 28p assuming this is the redline of your engine also you might be right where you need to be. Unless you wanting to spin the 32p at that same rpm

You could try a 30P using BBlades loaner/test program to see where that would put you.