Re: another holley power valve question
Basing the PV selection on idle vacuum is BAD advise that has floated around for a long time. If you take CRUISE vacuum, divide it in half and add about 2" you will be close. You want the PV to be closed while running a steady cruise, and open when the load is enough to require more fuel. Idle has nothing to do with it, even if the PV is open at idle the idle feed restriction is so much smaller the open PV will have no significant effect. Much like drinking through a coffee stirrer, it don't matter whether it's in a cup or a gallon jug, you will only flow so much through it. This is by one of the best carb tuners out there.
1967 camaro, 327, 9.7 CR, comp cam xs274solid, vortec cylinder heads, edelbrock vortec performer rpm, 750 annular carb, HVH 2" spacer, msd pro billet w/6A box, turbo 350 trans, 3500 stall, 4:10 gears, caltracs suspension, m/t drag radials.