I will give you as much info as I can on the short time I spent with the car this weekend.
An older gentlemen that I know stopped by this weekend with his 69 Charger.
Car was last driven about 20 years ago. He is trying to get it safe so his grandson can take it to the prom.
The car has a non matching 440 that was a replacement engine at some point in its life.

The problem is the car runs fine with its lights on for about 10-15 minutes then something appear to be heating up and shutting off the lights, all of the lights. They will come on an off actually.
After the car cools down the lights work fine for about 10 minutes again.

This is what I know after spending a short time with the car.
The engine harness is the original harness that is a total mess. I am quite surprised it runs so well. There are splices and wire nuts everywhere from the horns to the alternator and about 6 at the bulkhead.
The front light harness is original too and has a couple wires that are very poor.

The car is running an electronic distributor that was converted over last year. They stated they took the insides out and changed it to electronic.
There is no ecu box and its still retains the original voltage regulator. I had no idea that was even possible.

The alt was putting out about 16 amps with a battery that has been sitting all winter with only a 10 mile drive on it to my garage.

The headlight switch was very hot to the touch when they arrived.
The dimmer switch is new.

So I recommended getting two new harnesses asap, engine and forward light at a minimum.
My question is what do I tell him to order for an engine harness with the distributor he is running.
I can have him get a electronic conversion harness but how is he running an electronic distributor with no ecu box currently.

Secondly what on this car would heat up and make the lights go out.. Would the headlight switch do that if it gets too hot/overloaded.
I am afraid he will buy the harnesses (which he must for safety at least) and will still have the light issues.
Thanks for any advise!