What's it gonna be on? I've got one on a 188 Sport. Came with a Vengeance 48-16988 prop (13 inch, 18 pitch). Only had it out once so far. 42 mph (not checked w/gps yet) at 5000 rpm. I expect to get more out of it after complete break-in. If I'm wrong about that, I hope someone will correct me. At that speed, could hold a normal conversation, no yelling necessary.