Wow, GREAT paint job! I take it you used a stencil kit? Which one?
I have a 16' Princecraft with a 74" beam. The 15" transom version is rated for 35 HP, the 20" is rated for a 40. The previous owner replaced the transom with an aluminum tubing one and raised it to 20". Then I added steering and a side console.
I was going to put on an Evinrude 40, but came across a 50 for a great price. They are the identical motors with different carbs, so I put it on, figuring I could swap hoods if I wanted to.
It runs great, but I have to be careful. If I pin the throttle and start trimming it up, around 36 MPH it starts getting really squirrely, and porpoises badly. I'm guessing it would top out close to 40, but I don't want to find out what happens at that speed.
That being said, it runs awesomely at 30 MPH and will do it with 5 people on board. In my opinion, 40 HP is the right max for this particular hull, as per the manufacturer's rating.
Even with the pods and aluminum transom core, I would recommend you stay about where the manufacturer says is safe. Probably about 40 HP.