I have a RINKER 262 CAPTIVA Cuddy with a 6.2L 320HP Merc and a bravo III 2.2 drive. It currently has a Merc bravo III factory 24P 3 blade counterrotating prop set on it, and the prop is way to small. The boat slams up on plane quickly, but it's top speed is low at 50mph, and it's at 5700rpm WOT. It's supposed to be 4800-5200rpm WOT. The boat's minimum planning speed is at 3000rpm as well, which seems high. Right now the boat feels like an old chevy truck with 4.56 gears in it.

A buddy of mine has an 1989 Scarab ~35 with twin 454s and TRS drives. He talks a ton of $H!t to me, but his boat tops out at 55mph. I think with the right prop I might be able to give him a run for his money.

I'm going to upgrade to a 26p prop set, as that will get my WOT RPM into limits. I'm curious is anyone has any experience with some of the bravo III props available. Lower cruising RPM and top speed are important to me.

1. SOLAS 3 blade. Cheapest I've found. I'm not sure if it's any good.
2. Mercury bravo III XR. Most expensive I've found, but I believe this prop is built for top speed.
3. Quicksilver Thunderbolt DPS. Marginally cheaper than the XR. I don't know much about it.
4. Hill Marine Four by 4. Great reviews, but it's a small company, and it's a counter-rotating 4 blade. That seems like it would have a ton of drag and sacrifice top speed.

Any recommendations, besides saying "get a faster boat"? (I'm looking at getting a Fastech or Baja in a year or two).

Three things
A 26 foot boat with a small block is not a go fast
You have 320 HP but it has no torque
Your tachometer is incorrect if your hitting 5700 rpm because your motor would come apart

Tach is waaaay off. Merc normally sets the rev limiter at 150 RPM above the upper limit of the normal operating range which for a 6.2L MPI means 5350 RPM. PCM will not let the motor rev above that.

First thing to do is get a shop tach and run the boat and get your true WOT RPM and GPS speed. Also make sure you are not over trimming the boat. From there you can determine your prop needs.

If top end is your primary goal, you'll want to stick with the standard Merc 3 X 3 prop sets.

For comparison, my 260 Chaparral SSi with a 496 MAG/Bravo III/26" 3 x 3 prop set has done an absolute best of 54 MPH GPS. Most days it is a 52 MPH boat. Boat is heavy at 5,400 lbs dry. Boat was slower at WOT with 25" XR's on it but had a better cruise RPM/speed. .

Agree with AllDodge based on what I'm familiar with . 502mag , heavy 25' boat 2.0:1 gears and 26" propset = bang on 4950 wot rpm I'd look at your tach accuracy.
You might already be at max performance .
I too would have thought that your rev limiter would have been hitting in a long time ago .