They are about the best shop manuals you can get. They are usually just like the oem manuals and have a lot more useful info than the other manuals you get at the parts store. For instance, I just ordered one for my Firebird, the manual for the 88 model year alone has 1000 pages of repair, diagnostic info, and pictures for every system on the car. My Haynes, which covers 10 years, 82 - 92, only has about 400 pages, and in many instances is quite useless. And, of course, because it covers 10 years, it has to cover earlier carbed models, and later models with the ignition security feature, both of which are not applicable to my car, so the actual info contained which is specific to my car is far less than the 400 or so pages.
I got curious to see what they have for Fords. There are some available for Fords in the 50s and 60s. One I saw was for the 56-57 Ford-O-Matic, $12.00. Another is the 57 Ford Supercharger manual, $10.00.
So before spending big bucks on used originals, and perhaps even new reprints, take a look there and see what you can get bran new.
Lawrenceville, GA