Thanks for the link.. I scarfed up a copy of the images.
That might be a GM manual provided to the civilian workers in the 'little Detroits' set up overseas.
The manual I have is a TACOM manual that covers 4 different beds.. wood only (Chevvy, 352, 353 and a Ford beds).
- p006.jpg (43.39 KiB) Viewed 12206 times
I agree that the manual on the G503 has to be late 42 or 43... the oval decal with the 'Use Senior MIlitary Filter' text came out in early 43 (the earliest reference I have of it is the 43 TM9-801).
If you can contact the poster, have him look on the last page of the index, copyright in the 40's required all material to be covered under copyright to have a date of printing on it due to the copyright actually expiring in a sane amount of time (28 years). That should at least give the date of printing.