Quote Originally Posted by 65ny
Does ignition timing directly affect the idle air/fuel mixture? I set the timing (by ear) on my '71 440. No starter drag, smooth idle. I then adjusted the idle circuit on the carb using a vacuum gauge. Everything seemed ok, but sometimes I can't leave well enough alone. I borrowed a timing light and set the timing to the factory specs. (My ear was way off) If I remember correctly, it was 10 deg BTDC. Now, the carb seems to be running rich. Is this somehow related to the timing? I can readjust the carb, but I would rather not start tweaking if there may be another issue.
Yes, the ignition timing effects the idle circuit. Once you have the timing set correctly, you will need to readjust the idle mixture.