Don't think you can go to a larger pitch prop and run faster, normally you will find just the opposite happens.  You drop the rpm and that increases the load on the engine, it does'nt get into it's peak horse power band and boat runs slower.   You DO NOT want to run a prop that drops you more than one or two hundred rpm below the manufactors recommended max rpm.   

When trying different prop comes into play is trying different blade designs but staying with one that keeps your rpm's up.   Prop blades are designed to provide extra bow lift, stern lift, bow and stern lift, extra cup to run higher in the water, even to the point they can be run with the blade cutting the surface of the water (chopper props).  Some may provide no bow or stern lift and have very little cup.  Then you have the unvented, vented, over the hub, through the hub and those that have over and through the hub exhaust.

All these different types are so you can match one to you're hull.  Different boats respond differently to various props.  Most bass boats like a lot of bow lift and extra stern lift, unless you're in one of those hydro-rockets like the Bullets and Allison's, they don't like a lot bow lift where Rangers usually like as much as you can give them. 

I have a 96 Stratos with a 150 and she tops out at 63. 17.9ft. 

Not to sound rude but,  How big are you??  that may play a role in you speed