Puzzled - Starting/Running/Idling possibly Electrical Issues

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He guys!

I have a 72 Mach 1 Q code car - 351C CobraJet, automatic with A/C. The car belonged to me in high school. I sold it to my uncle in 79 and recently bought it back. It is almost bone stock original, even has some of the stupid things I did to it as a high school kid still in place. It sat for 23 year without starting. I replaced the entire fuel system, refreshed all the proper components and finally got it running. I went though the carb (4300D) I think, but it never would idle and run right. The distributor was stuck and broke as I tried to remove it, so I replaced it with an aftermarket point distributor (should have went to electronic). After 4 attempts to rebuild and readjust the carb, I finally bought an Edlebrock AVS carb with a spacer and replaced it. I have very carefully installed to assure no vacuum leaks, all the linkage performs as intended, etc. I am getting 6 pounds fuel pressure and have plenty of gas. I replaced the original coil (which tested good) with no change, and I have tested the incoming voltage to the coil as 5.05, 3.35 on the cold side. When running it tests 11.29 on the hot side.

The problem - sometimes it will start right up, maybe idle good, maybe rough idle. Sometimes it will not start. Seems to start easier cold. Sometimes it runs as smooth as it did in 79, next time it spits and won't stay running. I can't identify any pattern, yet it intermittently will start (maybe) and run (maybe).

I am a fairly good mechanic and have stared at this thing longer than most cars. Could I have a faulty resistor lead running to the coil? Bad ignition switch, etc. The battery voltage only reads 11.29, which should be 14 something I would think. I have no reason to doubt the new carb is bad, but am puzzled!

I am stumped - any ideas from you pros?
 
First thing I would to do is to charge the battery fully and have it load tested. It should have a resting voltage of 12.6V, anything significantly lower indicates a problem.

If good battery voltage doesn't solve the problem, I'd start looking into the battery cables, connections and especially the grounds. The 71-73 cars have a ground connection that is attached to the lower mounting screw of the voltage regulator. It's common for that to be missing or disconnected - which will cause all sorts of odd running issues.
 
Finally figured it out - the condenser was bad! This aftermarket distributor had a very small condenser that looks like a Chevy but smaller. I changed it out to a Chevy condenser from my 64 Impala and it hit and ran like a top (sorry Ford purists). Numerous tests drives since and it runs great! Dang $6 part!
 
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