There is no central source per se.....I have a few diagrams that Papajam graciously supplied, as have many other BB members......if I see a post asking for one, and I have it, I send it.
I do not have one for a '72, but perhaps someone out there will
Trouble is, they need to be looking into this thread (which is titled wiring diagram for 84) to know.
Something needs to be done. It would be a crying shame if Jim 'papajam's work just gets piece-mealed like this.....there needs to be a central library of his fastidious work set up in a sticky somewhere.
But I suppose that all needs to be worked out by BB and his family.