Need help with a Dodge Charger question.

We still don't know what lamps @cruiser has in this car.
This came up because it would be a clue as to whether its more likely the wiring saw higher loads than it was designed for.
That said, the failure description was that the battery circuit was wildly fluctuating from charge to discharge.

Yes original 4001, 4002 would place less load on the system than some later replacements. And my understanding is that depending on the hours of use and condition, some older sealed beams do a better job of putting light on the road than many of the current replacement lamps.... :(

Regardless, in terms of lamp efficiency, a properly built and installed relay harness will reduce the resistance of current to the lamps.
This means less heat in the original connections and wires. Equally important it means less voltage drop on the way from the alternator to the headlight.
The impact of a lamp seeing lower voltage is described here. Daniel Stern Lighting Consultancy and Supply :)

I'm not against people using original lamps, especially in a car that is meant to be as original as possible. I gave someone an appropriate sealed beam specifically for that purpose. But for those that want more effective lighting for driving at night, its nice to know the options that are technically sound. Just like a lot of replacement parts on the market today, many things are not as well made or even as well designed as they used to be. :(