Charging system

I would say the factory team had a reason for just about everything they did. Some of us are now old enough and experienced enough to now be a bit humbler about "improving" the "stupid" things the factory did. Also maybe a bit wiser in asking the factory system to do things it was never intended to do (like 'just' adding EFI)

Posts 13 and 14 cover the main circuits and the gages-sending unit circuits.
https://www.forabodiesonly.com/mopar/threads/66-barracuda-gauge-problems.577225/post-1974980612
Headlight and parking/tail light feed. (Barracuda in '66 might have front parking lights go off when headlights go on, In '67 they stay on)
https://www.forabodiesonly.com/mopa...-engine-wiring-harness.580727/post-1975045872
Dome light
https://www.forabodiesonly.com/mopar/threads/dome-light.509023/post-1973754122