My 12 ft Jon needs more speed!

Hey guys I got a 1232 flat fully decked, with wood and boat with motor is just shy of 300 pounds. I picked up a low compression 84' 15 hp Johnson, pulled the head milled .015 off the head as it was warped, I'm at 135 psi both cylinders, hell ya!, anyways, I put a jack plate on as my boat has a 12 inch transom and my engine is 16 inch so I got that squared away, I did a shake down test this weekend with me, 130 pounds and a buddy 200 pounds, our gear maybe 40 pounds and 3 gallons of fuel, 24 pounds. The boat sits nice and the engine is a beast I was cruising just under plane 5 mph or so and I would get the throttle pretty aggressively and this thing puts you in the seat and pulls hard but runs out leg and pegs out maybe 18 - 20 mph on glass, as fast as my uncles 12 foot heavy gauge semi v with an old merc 9.8 with no jack plate fully loaded. This doesnt seem fair as I got more power and pretty equal weight with his buddy and his gear and the more weight his boat is. I would like to take my really hard acceleration and turn it into smooth rev with a nice top end, from what everyone says to me I should be pushing near 25 mph, this is my first boat and don't know much about props, what should I be looking for in a prop, my current is a 3 blade 9.5 x 10. My uncle runs a 2 blade but don't know size or pitch, so I'm looking to you guys to help me out s little, just want to get a good speed instead of heavy acceleration, thanks guys!

It's really tough to recommend a change without knowing your RPM at WOT. You really need to have a tach to see what RPM you are spinning now. You want to be in the middle of the powerband at WOT.
If you have plenty of "power", but not as much speed you will want to increase your pitch size (2nd number).

Probably need a 9x11 or 8.5x12 possibly

Thank you for the response, I'm going to look into a tac for sure, for my application would a 2 or 3 blade work better?