Stock QJets are 750 cfm except for a few early 70s 850cfms off hi performance 455s.
Plug off that vacuum leak at its source and see if it helps. If it's from the A/C, factory source for that is a hollow stud on the right rear of the carb. If not in the factory location, trace the rubber vacuum line where it comes out of the firewall near the A/C box and windshield washer hose.
Vikki 1969 Goldenrod Yellow / black 400 convertible numbers matching
