Another easy question for you guys, my 440 Challenger has a serious stumble when I try to accelerate in any gear at low RPM. If I really try to get on it, it'll backfire thru the carb. It's stock electronic distributor and Edelbrock 1413 Performer 800cfm carb.

Hint #2: It smells like its running too rich at idle.

I think I had the timing advanced a bit too much before (I can feel the power loss when I go too far) and may have backed it off a bit too much.

I know I should get the timing light out instead of doing it by ear (and tick marks I make on the distributor housing), but...I've been real leery of using timing lights ever since I was a teenager and wasted a lot of time diagnosing my 318 until I figured out the problem was caused by a stretched/jumped timing chain and using the timing light was giving me worthless readings.

Put a timing light on it!

Yep you just have to know initial and total timing first.

One time I got some bad gas and ever since I've been real leery of putting gas in my car. put a timing light on it

I'd check out the AP squirt (amt/duration) & set the timing at 15 on ported for a good start (note (& post) what it is now when you check/set it)