I tried a bunch of different props on mine and the 4 blade 13.25x13 pitch 4 blade just happened to work the best. The 13.75x13 pitch 3 blade was a close second and is my backup. I do have one more Solas 4 blade 13x15 pitch that I tried and I’m looking to sell it if interested. I turned 5500 rpms with it if I remember correctly.