27' prop ?
 

I have a 27 fountain stepped hull. Dyno 6700 ft tq @ 5100rpm, 690hp @5400. Currently running 26 4 blade hydro 5200rpm all trimmed out and getting 78 on GPS is best I can do. What should I try for more top speed? boat planes out easily now just looking to get over the 80mph mark. I found a 3blade mirage 27 used for $225 so I have that coming, is that a good start you guys think?

27 Mirage is not the right prop for a stepped hull Fountain. It may not even get on plane with it.

Thanks for the advice. From what I have read I thought a 3 blade was faster and could run a little more pitch than a 4 so was thinking that was a good idea. Guess I'll be selling it

I would talk to bblades and get your current prop worked/labbed and I'm sure he will be able to get you to 80...unless the prop was already worked...he would also be able to steer you in a new direction if prop replacement is necessary