[McGillicuddy]

My guess is to get 73 gallons in, you pushed your gas can forward helping to offset the hefty motor.
Presumably this is a repower or you'da offered previous performance numbers.
Probably need a 14-1/2 x 17p stern lifting prop.
Consider going to prop shop and asking to borrow a Merc black max/quicksilver black diamond in said dimensions. It is a simple prop, that is easy to turn and cheap to buy, but does what it's designed to do (lift a heavier stern) as well as any. If you can spin it up to top of desired yammie rpm range with full load you'll be in the zone. After that my guess is you'll want to go 4 blade and stainless to add aft lift and handling at lower speed, and likewise reducing minimum planing speed.

I think it's a bit of a crapshoot cuz of the stocky motor and added fuel.