When I bought my 1995 single step Fountain 35 Lightning it had a pair of Mach sterndrive 26p 4 blade props on it. I have the original preformance test when the boat was new and it showed 14.5 27p 4 blade I assume these are hydros. Any sugestions on props I am running bone stock 502MPI's and with these props the motors will only turn 4500rpms at about 74mph on speedo

What props are on it now? The 26's or the 27's? What is your gear ratio?

It seems you are hooked up real well. You may need togo down in pitch to get the desired rpm.

Fountain Performance reports are typically pretty close with pitch (speeds may be another thing ) but prop pitch and RPM are usually correct from the factory. I haven't seen Reggie miss the mark like that. I am assuming that at 4500 RPM you are trimmed for speed, correct? I think you may also want to consider verifying your data. Your tach has some time and age on her now as well. I just don't want to make a recommendation that sends you off chasing ghosts with your dial in work. It may just be that you need to reduce the pitch to increase your RPM.

If you can give me your gear ratio and speed via GPS we can take a look for you.

Julie

On my '99 35 single step w/ 502 magnums I ran 23 P Mirage plus props. I got 5100 RPM and almost always saw 78-79 GPS. On a few occasions, with light fuel and passengers, I saw 80.3 on the GPS.

Hope this helps.

T

Would a mach stern drive 4 blade have 15 1/4 dia like a bravo? I see the 27's were 14.5 dia,wouldn't that make a big difference? Did boat origanally have 1.50 drives and maybe get changed to 1.36s along the way? Smitty

those are some strong running 502 Mags
My '99 Single Step 35 never seen a real 80 when I had stock 500HP's . Never heard of any late 90's Fountains running 3 Blades (and your ratio had to 1.36 to be anywhere in the ballpark speed wise)

The ratio was/is a 1.36.