currently running factory supplied prop Maximus 5-blade,15 5/8 x 28. Formula Fastech 2006 353 w/525 EFI's. Turning 4700 rpm @ wot. 80 mph gps. What size/type propeller to maximize available rpm?

Do you have boxes or ITS????

My freind has 500EFIs, Stellings and 30" bravo's. He gets about 84mph. You should easily get 85mph+ and you need to get the rpms around 5200. You would need to come down 2" in pitch from the 28's you have now.

Don't switch propellers. Let's get the big pitch to turn higher in the recomended range. Have them Lab Finished. Your efficiancy is excellent right now! We can get 400 rpm out of those propellers. 5mph gains are within reason!

If you like the way the boat handles and performs over all. Stay with these propellers. You already own them and the propellers can be adhanced to optimize the performance. If we go to 4 blade propellers you will lose cruise speed to only gain a minor amount of speed over the Labbed Maximus propellers.

I do not have boxes or its. Bravo xr drives with 1.5/1 ratio.
I was under the impression that these props are labbed at the factory, cant by them any other way.

Oh you can buy them box stock every day. I sell them in a variety of configurations.

I used to take all the orders from Kim Post at Thunderbird for all the Mercury propellers. The props you have will be stamped on the top near the prop nut if they have been worked by Mercury. Check there and let me know what you find. We can discuss it from there.

I was finally able to get to my boat this weekend, the props are already labbed. What would be the next step.

Can you supply us with the hand stamped serial # on the hub of the propellers? Then we should talk about it. Mercury changed their formula 3 times for these props after I left, only to return to the recipe we originally developed. Since you have a 2006, you probably have the latest and greatest. This means other options could be investigated.

The hand stamped numbers are:
Starboard; P11ul or Pl1ul.
Port; C11ul or C1lul

OK you have pretty standard templated Labs. There still are things to be done to the propellers to increase the rpm and the top end speed. We will need to see the props to make the ultimate decision but, I think a very small diameter decrease with thickness adhancements and a couple tricks could get you to the 5000 mark. This will maintain the cruise and really help the throttle response and WOT speed.