I agree, I believed the 2" below idle vacuum method and used a 6.5 PV. I have an A/F gauge and noticed a pretty severe lean condition at part throttle. I run about 17-18 inches of vacuum at cruise, so I will probably switch to something like a 10.5 PV so I will get some enrichment to help the part throttle stumble. Once I sort that out i may be able to lower the primary jetting.