1971 Plymouth Duster with 3.7 225 Slant six Idles very rough

67Dart273-
You were dead on correct about my Duster's rough idle. The Petronix distributor was installed incorrectly, causing the "Rotor phasing' that you had mentioned. Took me several months to get back to you, as I've had foot surgery, and been out of commission for awhile. I did want to thank you for nailing the problem directly!!