Currently have a '99' 35 Fountain with Whppled 500 EFI's, 1.36Bravo 1 drives with nosecones and stock Bravo 32's, this set up is getting 97-98 gps @ 5300-5400 rpm's. My rev limiter is set @ 5800. How would a pair of Hydro P5 29's work? I also have a pair Imco -2 shortys that I have not run yet. Top speed is my priority here!

Do you have Dynos? I have calculated your slip at 15% using 5350 RPM at 97.5 MPH. Fountains do appreciate a little more slip, so the Shorties may indeed be beneficial. Of course your RPM will increase, but this may also be beneficial, if your peak HP is produced at an RPM higher than the 5300-5400 you are currently running . If so, then 5B props would be the ticket.

Here is Whipple's chart, it shows peak hp made above my current rpm range. Do you think the P5 29's will give more top speed over my Bravo 32's with the -2 shorty's?

I ran the almost the same engine combination with a Whipple with the same gear ratio, and a pair of 29 Q-4 Hydro's. Standard length gear cases to 104 mph. This was on a 2000 35 Lightning twin step. It wouldnt get on plane worth a damn, but once it fell over, it was very quick to 104. I maybe had a bit more motor. They were 540's with AFR heads. The 29's were worked a little to let them spin to 5800. Just a little cup taken out. They had no diffuser ring on them and were worked by Hydromotive. In our application the Hydromotives were always a mph or two faster. That was 4 years ago. Im told now that they can lab a Bravo and its just as fast. Those 29's were not labbed. Stock except for some cup removed. We ran 5 Blades also, Im sure you will find that they are great for everything except top speed if you are going to run you standard length gear cases. They are too deep in the water. They have to be surfacing a little to appreciate how great they can work with higher X dimensions. When you go to the shorter gearcases, the P5's will really shine

I would think from viewing your Dyno that you should run at about the 5600 were the Dyno run ends. I would think you would not want to run less than the 5300. Again if you install the shorties then 5B props will most likely perform well and any semi-cleaver on a Fountain usually delivers on top. I would encourage you to this set up since you have the shorties. Let us know how things go.

Any prediction on speed with the P-29's?

Hard to say, as with the shorties your slip will increase. But, Fountains like a little additional slip and really respond to reduced drag. This typically results in increased top end.

I'm a little concerned with your current slip%. I actually figure it at 16%. Fountains can run faster than some with slightly higher slip #'s. There is a limit however and your getting closer. If speed is the only concern, and it is here, I will tell folks to not worry so much about the slip. Let me worry about that and you worry about the speedo.

If you go to the shorties, the Bravo 1 propellers will most likely be out. The slip will climb too much and ease of drivability and turn key operation will change. Using the shorties and a 5 blade propeller may indeed increase your top speed slightly.

I see the dyno sheet flattening at 5400-5500. I would prop there. Also, is this your actual engine sheet or one that reflects these types of install?

The dyno sheet was from Whipple's website and probably reflected average results. What do you mean when you say the higher slip will cause me to lose ease of drivability and turnkey operation will change? Any suggestions different from what I have planned?

Mostly is was refering to the ability to get on plane and tight turn ventelation. I was using the Bravo 1 and shorty drive scenario. It may not be as user friendly as the lower X and the B1's.