I realize this isn't exactly your boat/motor combo, but, it's also not too far off. I have a Yar-Craft 186 w/200HP Yamaha. I switched from a doggy-out-of-the-hole 20P Yamaha prop to a 19P Merc Enertia prop and it made a huge difference planing out, especially with another person or 2 in the boat. I didn't lose any top end and with a couple passengers the 19P is faster than the 20 was by ~2MPH.