I have a 23p prop on a 24 captiva running 4300 rpms wot at 64 mph I was wondering what would be a good prop to run but I was thinking of a 21p rev 4 to put me at 4800 rpms at wot. Any suggestions?

Need a little more info to help with your selection.

Which 23 pitch prop? 3 blade? Mirage? Laser etc...
What is the drive ratio?
What motor do you have and what is its rated rpm range for WOT?
Is the speed GPS?

One of your current numbers is amiss since it is not possible to run 64 mph at 4300 rpm with a 23" pitch prop assuming you have a 1.5:1 drive ratio. Make sure to get a good GPS speed.

A 21" Rev 4 may increase your WOT rpm a little, but I'm not sure you will get 4800 rpm. My best guess is you'd see 4500-4600, but that is a rough guess without knowing the other facts.

Agreed. Also, the Revolution has so much blade area the chances for increasing the rpm over a 23 3blade Mirage is minimal and even less if the 23 is a smaller casting.

Brett