I am currently using and 05 Cougar with a 250 Yammi on it. It also has the 27 T prop on it. Slow coming out of the hole but phil is right. Will flat out role on top end. I have seen 81 mph with 2 people, half gas and full tackle load. Believe there is a little more also with a little tweaking. I am in the process of setting this boat with a 26 Trophy to see what I can do with it. Thought this thing would hit the rev limiter with it so I dropped the motor first time out with it. Was wrong, although I like the way it comes out of the hole now and mid range punch is better. I lost some on top end and still have some left as far as hitting the rev limiter. Top end was only about 76 with about 5600 RPMs. Just got done raising the motor back up yesterday. Hope to turn a few more RPMs and increase the top end just a little bit. Will see next week when I hit the water !! Good Luck