Evinrude 31.8ci Mod Advice

[Emustard]

I posted a form a couple of months ago asking for peoples info on mods to a evinrude 31.8 cubic inch. over the winter we did some modifying, and were a little surprised with our results. we thought we would be in the high 6000rpms with the 10-15 ss and we were not close. what do you think our problem is?? I added some pictures so you can see how our rig is set up. Boat is 14 feet long with one person in it and motor and gas is 600lbs.

NOW
compression 147psi top, 152psi bottom
port and polished intake and exhaust
Wiseco pistons
intake manifold increase in size
boyesen reeds and opened reed stops
tuner shorted an inch
vent exhaust above the water
1.50inch carb 83Main jet 40air jet


BEFOR
before we were running 125psi in both cylinders and the boyesen reeds. that's it
1.50inch carb 77Main jet 40air jet

The props are a stock evinrude 10-13 aluminum and a solas Stainless steel 10-15

OLD TEST
aluminum 10-13 prop @ 32mph at 6150 RPM (1 person)
4people in the boat 100lb of gear 29mph @5800 RPM

stainless steel 10-15 @ 33mph at 5550 RPM (1 person)
3people in the boat 29mph @5200 RPM

NEW TEST
stainless steel 10-15 @ 34 5600 RPM (1 Person)
3 people in the boat and 100lb of gear 31mph @5300RPM

On the new test the engine has all kinds of power getting up and out of the hole, a lot quicker then before also runs the best it has ever but still thought it would have more power at top end.