That sounds ok. According to the current Zodiac brochure, recommended power for the Pro Open 550 is 90hp and they list a max speed of 45mph (about 39 knots). You may or may not find a better matched prop but as Hightower says, you'd have to try them out to compare.
For comparison, my Pro Open 650 hits 41 knots (on the GPS) which matches the brochure, but is going over the maximum rev range for my engine so I'm looking at changing from a 19" pitch to a 21" pitch. Unless you are also over the maximum revs, you should be good.