I'm completely stumped guys. I've got gremlins hiding somewhere in my engine, and they're confusing the hell out of me. Here's the rundown. I started having battery problems. Had the battery/alternator checked, both of them are fine. Noticed the belt tensioner was moving back and forth a bit, relieving tension. So, replaced that, and the problem is fine. Except when the headlights are turned on. Now whenever I turn the headlights on, the battery meter on the dash drops from 13 to 6 or 7, and slowly idles back up to 8, which is too low to operate the radio, and barely have the headlights on. On top of that, when the headlights are turned on, the car starts to run rough. Once it's down that low, it will not go up higher unless the headlights are turned off. The battery meter will go up about 1/4 of the way between 8 and 13 if the car is idling, which really makes me think it's the alternator. As I said, however, I had that checked, and I replaced the hot wire and ground wire from the alternator.

So, what's the correlation between my headlights being on and my car running rough, and the battery not charging? It's a 100 amp alternator, putting out between 95 and 96 amps.

 

If the lights were the source of a huge draw, you would blow a fuse.
My Chrysler had two out of three diodes bad, from the beginning, giving very few reserve amps to charge the battery.
But I digress. If you really are putting out big amps, it must be the regulator in the alternator.
Also, as you have not indicated checking engine to chassis ground, please do so. My '83 has aluminum wires, which as we all know, do not stand up to flexing, as well as copper.

Seth