I'm on my second season with the above mentioned boat... I ma running a high horsepower built 496 ( 550 + HP) with a bravo drive, I ran a highly modified 3 blade 27P prop last year and reached and even 70.... I detuned the motor a bit this year with a smaller cam and was only ably to turn 4500 RPMs. I purchased a 25 P mirage and can now barely make 60. it seems l ike the boat wants a 26P is there even such a thing I would love to hear what anyone else has experienced..

each prop size up or down should give you close to 200 RPM so if your only turning 4500 with a 25 you should try a 22 3 blade ? i would go with a 4 blade over a 3 blade any day , A 4 blade is +1 for pitch so a 22 3 blade is a 21 4 blade. Why did you de-tune ? Reversion ?

I may have not been clear in my rpM range.. I was only making 4500 RPM with a 27P prop..

So what were the test #'s for the 25?

Did the cam swap drop you under 500hp? I would think with 500hp that engine and boat should be able to swing a 24-26p 4 blade.. Are you absolutely positive that the engine produced the power you said it did?

Fleg, my RPM's can exceed 5100 rpm (58/61 MPH) but my cruise speed at 3K has dropped dramatically from 39/41 MPH to 34/36 MPH..... it seems to me like a 26P 3 blade would be the answer? Is there even such a thing?..I don't believe my HP is below 500

Only way to get a 26 3blade is to have a 25 lab finished.. If your after top mid range speed go with a 4 blade bravo1 prop.. I would try to get your hands on a 26 B1 to test then take those results and figure out what you need to get the engine where it needs to be..

Call Bblades and talk to Brett he can lead you in the right direction..

issue:
1988 Baja Force 320 getting only 51 mph with SS 25p props turning only 4k rpm...stock BB 330 merc.
Repitch to 23p mirage to get 4800rpm and be in low 60's? bow lift seems hard to get to...thinking about buying the boat...

You need 21pitch props with some cup added to carry the bow of that 320..

Thanks Fleg...have you tried the 4 blades over time too?

When I first bought my boat it had 365 mags with the drives very deep in the water at that time I ran 23 mirage plus props. After I rebuilt the boat with new transom, bulkheads and stringers I raised the engines and drives 3" which put my prop shafts at 4" below the bottom. After I did that 3 blades wouldn't plane the boat off! So I went to lab bed 24 bravo 1's the boat ran good about 66 ish. So I wanted more I put extension boxes on the boat, which improved the handling a lot boat ran about 70 after that, I blew a motor up so I decided to put 502's in it, I installed bigger cams and better valve train to get them to 500hp and today I'm running 80ish with 28p bravo props at 5000 rpm. I still have more in it, I need to get my props worked to get my rpms around 52-5400 and it should run low 80's..

So the answer to your question yes I have played around with 4 blade props...

Unless you have high x did pension on your boat I think the 3 blade is your best bet!