[fastd]

I have been dealing with a similar problem myself recently (subject is "WOT too Lean")

Please feel to disagree, but I am tuning my PVs only to WOT. I have 4.5s with a idle vacuum of about 11.5". If you agree, then increasing your PV to 6.5s is not the answer; but it could help.

IMO, a vacuum gauge and A/F gauge will help you more than taking it to a dyno unless you know the guys running the dyno are really interested in getting it right - it takes a lot of testing, tuning and patience to get it right on the dyno. You definitely have already demonstrated that you are willing to put in the time and money to get it right...but are they?

Given your situation, I wouldn't hesitate to jet the 2ndary main jet way up to see what happens. Really an a/f gauge can best tell you whats going on at all of the various stages; more efficient that anything else you can do. If you do jet way up, I would keep the 4.5 pv, got to WOT immediately to see if the engine feels good. Tuning for WOT is easier than tuning for both WOT and pre-WOT. If it does, then see how it feels pre-WOT and take it from there.

I have spent a lot time jetting the PVCR, the emulsion air bleeds, the IFR, the high and low air bleeds.

If it is indeed a carb issue, i.e. not ignition, etc. then there is a lot more you can do to tune specific parts of the curve than just main jets...

Curious, why did you take out the efi?