Intermittent total loss of electrical

Since you obviously will be driving in the dark with this car, let me bring this up now. Our cars came with 6012 headlight bulbs. Many replacement headlights since the mid-70s use more power than the 6012s did. The headlight wiring circuit is long and has many connections, and the wiring is only 16 and 18 ga in our A-bodies. So for your use it would be worth considering a headlight relay circuit. You can make your own, buy a kit from Daniel Stern, or buy a premade, almost plug and play from Rob Yule (screen name crackedback). Power it off the alternator and that will also take about 9 amps of current off of the bulkhead connectors.