I am rebuilding my 850 DP. Running a procharger with 9lbs of boost. I was told to plug the power valve on the primaries and add 4 numbers to the primary mains. I am running 90's now and going to 94's.
Also what about getting rid of the secondary power valve to, do I need it? I have 100 mains in the secondaries now!

The carb is about 7 years old!

Thanks in advance

You should run PV's in the primaries and block the secondaries.

Is that carb set up for a pro charger. Some of the carbs run a boost line to the power valve so it dont close and lean out. Be carful if that is a stock carb you might burn some pistons.

Griff, what is the reason to just block the secondaries and not the primaries?

Think of a PV as jet that opens with decreased vacuum and increased rpm. The primary PV will open and add fuel say from 3000rpm and up because vacuum has decreased. By the time you're into the secondaries, around 4000rpms, the secondary PV will pretty much always be open anyway. Instead of using a PV, just increase the jet size.

Dean Nickerson is THE man when it comes to centrifugal blower carburation. He sells a bolt on carb calibrated for that application. I've been there, Nickerson is the best.

Kurt

griff is rigth that is how my carb set up i try putting power vale in back and i got more speed with out . i change jets power vale took the boat for test runs all day long . at the end of the day on my gps i gain 2.9 mph .

Thanks for all the input. I am going through the carb now. I am also going to pull off the manifold and reseal it.
The power valves that came out were 3.5's and the pri jets 90, sec 100's.