Got Shell 93 Octane and now barely idles 1973 Dart 340

So was getting rid of the old gaskets the trick? If so, then the rich settings may have been needed to compensate for vacuum leaks. Idle vacuum may be lower now due to the idle speed being lower....

If it is cranking a lot before firing when hot, then it could well be too hot fuel boiling in the carb. High ethanol content is worse. May be time to add a heat shield under the carb, like this one: Holley 108-51, Holley Insulating Carb Gasket Heat Shield | Holley

Double check to see if this one fits your AFB. There are other types out there.