I recently acquired a large binder of 1947-50 New Orleans Zone documents. I have just started through them but some interesting items are in there. I will post more as time allows.
https://www.flickr.com/photos/advance-design_parts_co/16870271246/in/set-72157631868452754
Recommendation on coolant and temperature for trucks equipped with the Fresh Air heater, later called Air-Flow. (1947).
https://www.flickr.com/photos/advance-design_parts_co/16708546208/in/set-72157631868452754
Another that shows a unique placement of the coolant overflow tank, the inclined position does not appear in any of my other documentation?
https://www.flickr.com/photos/advance-design_parts_co/16870271926/in/set-72157631868452754
https://www.flickr.com/photos/advance-design_parts_co/16710022999/in/set-72157631868452754

1950 Chevrolet 3/4-Ton 3600
More pictures on Flickr