I have a friend running 29P mirages on his boat but he is looking to go to 4 blades for easier plaining? I guess. Anyway, I am just wondering what prop in a 4 blade would offer the same WOT rpm. And is there a difference in a Bravo or hydromotive?

Bret at bblades just informed me that a 29 mirage + actually measures closer to 30 pitch. I would think you would have to look at his prop slip numbers at WOT in order to decide between a 28p or 30p bravo.

What kind of boat? What power? What rpm? What GPS speed?

The boat is a Baja 280 sport, 502's 525hp each, 5000 rpm @wot 78 mph on gps. And they are actually mirage plus like you said.

Looking for best cruise speed without losing to much on top.

for reference I ran 27 Mirage+ and also 26 bravos on my boat, so I would think the 28 bravos would be the best starting point for you. I have also run 28 Bravos and they are definitely a taller gear than the 27 Mirage+. The only way to know will be to test them out every boat is different.

I'm no expert before buying anything I would consult experts like Bret at Bblades there testing program would be perfect for your friends situation. But my opinion is the 28p bravo1 would be the best starting point. It takes allot to turn 30p's,

Testing is the only way to know for sure since every identical boat is different.
However, the 30 B1 is really 29 pitch so that would be the first option.
We can send you both through our test program.

Brett

Tell me more about the prop test program.....

Here is a link to the test program page on our website.
Call if this interests you and we can go into the specifics.

Brett

A stock 30 p bravo 1 ran the same rpm as a Mirage 29 on my Formula 311

Oops, here's the link.

http://bblades.com/propeller-test-program/

Brett