Except at one time most of us would go to a book first. Owners manual or something like that had all the basics. Firing order sometimes cast on the intakes. I don't have a photo but on my '67 someone had neatly scratched the /6 distributor sketch on a an inner fender.
Waiting for someone with more /6 knowledge to tell him when tubed spark plug heads were last made. I need ot spend time looking looking up and figuring out my own mysteries. All I wanted to do was set the alternator bering at the correct hieght. This resulted in figuring out the C- (Miller) and SP- (IDK?) tools which changed over time....