I'm helping a friend dial in his 1989 27ft Activator. The boat is currently set up with an XR and a Bravo lower with a LWP. The motor is a 565ci making approx 650hp. The prop shaft is approx 3.5" below the bottom of the boat and we are currently spinning a labbed 28" Bravo turning approx 5600rpm at 80mph, 19% slip!! The prop does't want to carry the bow! I'm thinking trying a 27 or 29" Mirage Plus? This is a non-step hull with the inner strakes running only a few inches from the the transom, certainly dont need to lift the transom! Any thoughts from people experienced with this hull would be appreciated.

I'd try a box stock bravo prop first.

We ran boat with new 28 Bravo, slip down to 14% from 19%, now 83.2mph at 5500rpm. Good improvement! next we are going to try a std lower gear case as opposed to the LWP. Last fall with a stock 28 and stock lower the slip was closer to 10%. The only thing that changed from last fall was more power in the motor. We shall see?

Only thing changed? Xz versious Xr?

Where did your friend end up?