I currently have a holly 750 with a 65 power valve. Is this the correct one to have. I have a 406 with a 535 lift came, 195 afr heads 68cc chambers so I'm at 10.2 to 1 or so. The cam is 108 lobe center and int/exh is same lift. 244 at 50.

2" below your idle vacuum, warm and in gear is standard. 45-65 is an approximate number for your setup.

I talked to Holley and they said to put a vacume gauge on it. Take the vacume reading and split in half and that will be the power valve for your car. I am pulling 9 in vacume and running a 4.5 power valve. 9 divided by 2 = 4.5. Good Luck!

I do it slightly different depending on manifold vac.If 12 in or higher I generally start with dividing the vac by two and adding one. IE if you have say 15 in the 15/2 = 7.5 + 1 = 8.5 PV. This allows you to actually go some distance on the main system without adding any unnecessary fuel as the PV really should open under heavier load. If your cam is more obnoxious then I'll also start by diving by 2 and fine tune from there depending on driving demands.... Any of these will get you in the ball park and then expiriment from there to really get it dialed in.Cars with loose torque converters generally require a slightly different tune up than a stock type converter , Low gears , heavy flywheels , wide ratios ,close ratios ect ect may require you to expiriment with things to really dial in your setup.

do you have one power valve or two? f you have one in the front and one in the real barrels how about having 5.5 in front and maybe 3.5 in the rear? the original specs on many of thes carbs were two setting below. ie. 10.5 and 8.5.
and what about the spring in the vac. actuator if you have vacuum secondaries? :eek: