'65 Dart-Lights flickered, lost electrical, loud bang, car died

Above is the cliffnotes version of what just happened to my car! I've got a '65 Dart 270. I was cruising down the freeway and noticed that my lights--both my headlights and my gauge lights--were flickering, but only between being dim and being bright. Suddenly, my car lost all electrical power, I tried pumping the gas, heard a seriously loud bang that scared the hell outta me, and I pulled over.

No headlights or electrical at this point, but my battery reads 12v. I did see some smoke in my rear-view mirror when I heard the loud bang, but I have no idea what that was about.

My hypothesis is that my electrical system got shorted out, and I'm thinking that the boom I heard might have been a backfire. There was never a burning smell, nor leakages. My battery didn't blow up, and the rest of my engine looks normal and undamaged upon visual inspection.

At this point, I feel like I've got a riddle on my hands. Any help that could be offered is WAY appreciated.

Thanks y'all!

Gabe
Seattle, WA