Originally Posted By Cab_Burge
If you don't have a OEM type factory service manual, not a Motors or Chilton service manual tsk then buy one now.
Mopar is great on their FSM on all the electrical circuits and diagrams up scope
Mopar has done some mid year changes like the 1969 1/2 390 HP 440 6 pack motors with the wiring needed for the idle shut off solenoid that weren't in the original 1969 FSM for both the Dodge and Plymouth B bodies shruggy I'm not sure if you can still get copies of the update to the FSM or not for changes like that.
I have done several complete restorations on mid 1960 to early 1970 Mopar B,E and A body cars, all of the factory wiring harnesses are plug and play up
I need to let you know I worked for a telephone company for over 30 years in customer services fixing telephones and telephone lines so low voltage direct current electrical issues do not scare or mystified me.
Nothing for you to worry about either up grin

I do have a service manual actually, you can download them for free from mymopar.com. I have it on my laptop and phone, I don't believe I'd have to worry about mid year changes or anything like that. Also, if I plan on swapping the 727 to an aftermarket manual, should I get the manual harnesses?