Welcome aboard from SE WI!
I will just ask you now since this search for a holy grail is been a hot topic... do you know where a guy can get one of these?
Greetings from Western Upstate NY, Pittsford (suburb of Rochester)! I am not certain how new you are to the world of First Generation Mustangs, but I thought I would share where my main GoTo web site is for all kinda of documentation in PDF files. It is Forel Publications, at the link below. Their manuals are priced reasonably. But, there are some "Oh, by the way..." issues you need to be alerted to. The wiring schematics before 1972, from Ford, are not nearly as well done as the 1972, and especially the 1973, colorized electrical schematics from Forel. I suggest you get the 1973 electrical schematic manual even if you have a 71 or 72 Mustang or Cougar (get those manuals also for 71 or 72). There are only a few minor differences between 1973 and 71/72 wiring. The clarity provided in the 73 manual makes it well worth the addition bucks.
https://www.forelpublishing.com/clickbank/index.html#Top
As for emission control related vacuum lines, Ford did not get serious about documenting the various engine vacuum line calibrations until 1973. The 1973 Shop Manual from Forel includes some excellent information and vacuum schematics in Volume 6. There are two calibrations for 1973 351C 4v engines that were not included in the Forel Volume 6 documentation, so I will attached a file to this post so you (and others) can download that set of calibrations.
Also, for 67-72 The Mustang Barn put together a collection of PDF files for the various vacuum schematic calibrations. With the knowledge and permission I consolidated all of their individual PDF files into a single PDF, grouped by year and sorted by engine. You are welcome to provide copies of the file(s) to anyone else you may feel can use them. My consolidated Mustang Barn 67-72 file is also attached to this posting.
