I have a 35-0 fountain ex with 496 ho the boat came stock with 32p wide open I am only seeing 68-69 if I change to 28 p will that give me more speed?I don't hear a lot on 32's from the factory.

What are your WOT rpms? You will raise your RPMS 200 to 300 rpms dropping to a 30p.
Also, if you lab your 32's, you could gain 200 to 300 rpms, while still turning a larger wheel,,,, better performance!
Carder

thank you Carder I am running 4900-5000 rpm wot

32" props running 68-69 @ at 4900-5000rpms?????

What gear ratio drives???? Even with 1.65's the prop slip is way high.

Food for thought what about 5 blades for alittle more transom lift ?

Slip is bad. Need to determine why first.

5 blade props can be the ticket on hulls like yours. The 4 blade props should be better than they are though.

please explain prop slipage why would this happen everything is stock.I still question the 32p verses 28p

You're already spinning the 32" props at the right rpm. 28's would theoretically spin about 800rpms faster. Your engines would be hitting the rev limiter at 5100rpms.

read this about prop slip
http://www.go-fast.com/prop_slip.htm

thank you Griff