I just purchased a Z-9 Nitro with the Pro XS 250, prop is a three blade fury 26. Top speed so far is 68 and to get there I'm throwing a tall rooster tail. Need some ideas to increase boat speed and knock down the rooster tail a bit.

either trim down or lower your jack plate if it has hydraulic. I would guess you are too high on the jack plate. The fury prop likes to run a little deeper anyways.

what rpm is it turning at wot? what load, full fishing/tourney load or just you and a little fuel?
is that gps speed or speedo?

Full tourney load, at just under 6000 rpm. That is the GPS speed reading

fishing or trying to outrun the bird and turtle man

sounds like you just need to lower the jackplate.

I would agree that you probably have a good prop for that boat and are just trying to run it a little too high. It seems most of the ones I see are running around 3" below the pad and getting a little over 70 out of the boat. It will never be a high 70's boat but should get you 72-73 if set up right.

http://www.stevescustomprops.com
Talk to this guy, he's the best I've ever seen with prop info and many will agree.. I have a 04 zx225 skeeter that will hit 74 with his prop work carring a tournament load...The guy is unreal... Trust me...

I am running a Z8/250 proxs with 26 fury I will run 76 Gps. That being said I went to a 25 fury better hole shot with 2 fat arses and full tourny load. As low as lakes are I run slower anyway.

Lower your JP. Should see 70 easily.

props to steves he is awesome!

you shouldn't be throwing a R-tail higher than you motor to begin with. You'll feel the decrease in speed the higher you go. The prop isn't getting the bit it should.