I upgraded my power this winter, went from a 365hp merc magnum 454 to a custom built 580hp 496. The 454 turned a 25P RH Mirage 3 blade to 64mph at 4600-4700 rpms.

Can you guys give me a good recommendation on a good prop for the new motor? I was thinking maybe a labbed 4 blade 28P might be the ticket

cjmatt,

I think you are right on the money. The power upgrade will require at least 2 inches of additional pitch. The 4th blade will aid in a variety of issues. Labbing the prop post your baseline stock performance numbers is most likely the best route. Let me know how it goes and of course we have test props you can try without purchasing.

Brett

OK, I plan on trying the boat out with the same 25P mirage this weekend and will let you know what it does

You may be surprised how close your current prop may be if your new engine runs a higher rpm. Id stick with a 3 blade if the boat handled well with the current M+

just updating this thread, I was able to hit 72mph with the 25P mirage at 5000rpms, then it started chinewalking so i had to get out of it. it was still pulling pretty hard so shes got alot left in her

You can drive through the chine walk. My buddy had an Agressor that ran in the 90's and used to walk from 82-86 then flattened out. Ill hit him up this week and see what prop he was using. What should your engine be spinning rpm wise? That is a **** ton of power for a skinny boat. A 3 blade will slip more but a 4 blade will walk the transom while in bigger water.

I also have an Aggressor running around 600 hp. We had the stock mirage 25P an it wasn't nearly enough. then we bumped it up to a 26P four blade bravo. Now it has a much more stable ride and we can run 78-80 with a full tank and four people.

I want to keep it around 5200 max. Rev limiter is set to 5400 at the moment. I only had one steering ram on the boat and just picked up one more. im hoping that helps stabilize it as well. I havent touched the tabs yet either, which should help stabilize it too.

What RPMS does it run? Any chance you can measure from the bottom of the gimbal housing to the bottom of the boat? im curious to see how the x dimensions compare as well

She goes 40mph at 3000rpm, 48-50 at 3500, and 78-80 at 5500.
I'd like to tell ya my x dimensions but my boats being stored 20 miles away as of now.