I think I have the right prop I just want to make sure

I have an 1983 Chris Craft Scorpion 18.3 with a 5.0 Mercruiser 200 hp. It has an Alpha 1 OD with a 14.5" prop with a 19 pitch. Today I had 4 adults 2 were at least 230 lbs, 1 was 175, and 1 was about 100. I also had a 2 year old and a 7 year old on board. So I had 4 adults 2 children that includes me. I was having a lot of trouble getting the boat to come up on plane. I had to move one of the adults up front and have him stand next to me while I was driving to get the boat to plane out. I have had 3 adults and 2 kids and not have had any trouble. The only other issue that I can say is I've never been able to get 4000 RPMs out of the engine at max throttle the best I've been able to get is about 3600 RPMs. If I was going to change the prop pitch or size anyone have a recommendation?

HI I have a 14.5" prop with a 19 pitch the WOT is 4000 RPMs. So how should I pitch the prop I don't always have that many people on the boat but I never can get the engine to run at WOT. I know that the bottom is clean and there is no water in her. If I only have 2 adults on board the boat will plane out pretty quick although it will still not get to 4000 RPMs usually goes to 3600 or 3700 RPMs.

Unfortunately I don't know the ratio. Yes it is a older fiberglass boat. I thought I saw a tag on the engine that said the WOT was 4000 but I could be wrong I'll have to check. I usually don't run it past 3000 RPMs anyway but on the rare occasions that I have an extra person on board I would like to be able to get the boat up on plane without moving people around so much.

if your carbed and running the 1.50/1.47 ratio ,thats a bit too tall for the motor. try a 14 x 17 3 blade and report back.
you may have to pull the drive to verify the gear ratio.