I have a 13-3/4 x 15 aluminum currently. Last year I was getting around 24MPH at 5500 RPM by GPS. Start of the year I was showing around 29MPH, but her butt got a bit dirty over the summer
At WOT, the motor would over rev well over 6k RPM, so I've been shopping for a new prop this year. I just picked up a used 13-1/4 x 17 that I'm hoping will take RPM's down a tad and give me a few more MPH's. Will report once the boat gets into the water