About 68 is what it would run. Thats based on the boat speedometer. According the the calculator thats the correct speed too. The thing I dont like the most is the hole shot, kinda slow. I pulled 2 plugs but the prop would slip way to easy, so I went to 1 plug pulled and its much better than 0 pulled. Still not great, and I seem to have lost some top end. Now the speedometer will only reach about 64 or so. It appears I need to start looking for a new prop.