The 27's are less diameter than the 25's. Consequently, you lose some leverage and bow lift. Also, the reduced rpm increases the torque loading on the drive train and props. This will exacerbate the lift on the 27's. If your looking for better cruise, than go with a bow lifting 4 blade that turn 5100-5200 rpm, if that is where the engines want to be.

Thom

The 27's are less diameter than the 25's. Consequently, you lose some leverage and bow lift. Also, the reduced rpm increases the torque loading on the drive train and props. This will exacerbate the lift on the 27's

Huh? not sure what this means.

What he is saying is the 27 prop is smaller in diameter then the 25?. I essentially do not want to turn these things at 5100, they are just stock 54's. I thought that adding the 27's would get me below that. Again I have picked up all over the board as far as cruise, all goes but would like or at least think the boat needs a little more lift. As per Fountain this boat came stock with 25's, which in my case was def def not enough wheel. So would a cup in these or rake increase the bow lift ? Here is a vid( don't have to watch the entire thing) As you can see the boat comes up on plane in no time, I am being very light on it never brought the tachs above 3500. Also this is with the TABS all the way out. Only drives down. As I said I have to keep the drives at about 4 @ 32-3500 to feel like the boat is almost riding normal, atleast to me, still feels kinda nosed over. Based on my reading everyone says that is too much trim for even WOT running, but I can pull the drives up even higher for WOT, only then it feels like it is trying to hang the bow. Also exp zero blow out..

https://www.youtube.com/watch?v=xVq8...Ik660M3iqRBRhg

John jr

Yes Mirage props change diameter with the pitch increments. My point was the theory mentioned doesn't make sense to me. The additional pitch can cause a extremely small amount of stern lift but the diameter reduction neutralizes that.
Anyway, adding rake via cup and a tip bend will give you more responsive trim.

Brett