Prop recommendation 15' Henry O with 50 HP Johnson

[LarryHale]

Recently bought a 1987 15' Henry O with a 50 HP Johnson motor. Current prop is 12 1/4 x 15 SS that has a flat spot on one blade's trailing edge. I'd like to get a little more speed out of this great little boat. This little boat has no instrumentation other than a trim gauge and I haven't had a chance to check speed by GPS yet. Any suggestions?

 

[Sea Rider]

Without knowing achieved max wot rpm range as loaded impossible to recommend any prop from current one. Need to know if OB revs at least middle to max wot rpm range factory stated. For that need to buy a tach, whether for dashboard or an induction one.

Happy Boating