mopar performance ignition miss

Hi I have 2 318's Scamp and Aspen also a 340 Demon. All with Mopar performance ignition. All 3 have a low rpm or idle stumble. All have different carbs. Spark plugs on the black side so lean is not the issue. At the moment I am increasing plug gap on 340 from .35 to .45. Anyone else experience this.
How do you know it's ignition? Idling in gear and you matt the gas pedal and it stumbles? Under what conditions?