Boat seems to be missing 10 mph and 700 rpm

[Striper80]

I have a 14 1/4 x 17, I'm pretty sure these are the numbers, apollo prop in my garage. Maybe I'll throw it on just to see. I bought this boat used about 3 years ago and I've only put about 40 hours on it. When I got it the GPS didn't have a speedometer on it so I didn't notice how fast I was going. After two trips I put it away for the winter. Over the winter I had the prop done because the PO nicked the prop. I also got the sei replaced under warranty, did the control cables, and installed the current GPS. My seat of the pants feel was about the same, but it was a bit skewed since I had to do the whole sei break in.
Last year I did the carbs, link and sync, and set the timing, cranking method since I have no test wheel. I had an issue with stalling going from idle to part throttle after that, but I seem have that handled after changing my water separator housing and draining the whole gas tank.
I hadn't thought about prop slip. I was only thinking that changing the prop would change rpm but not overall top speed. Since owning this boat I've always felt that it had less punch than my Striper 2100 WA. That boat was 21 from pulpit to stern and this one is 23, but that boat only had the 130 on it.