Hi Goncalo
Well here is the cover and drawing for and Autocar U8144 that I know was used by the US Navy at White Sands New Mexico or China Lake California as a support and tow vehicle for Navy Ground Fire Control Radar. Was in with my fathers work stuff from his work on that equipment. There are more dimensional drawings if they would be of help.
I know I've seen the more info on the Autocars you are talking about. I'll have to do some thinking about where they might be. There are a couple of US Navy Links that might be of interest to you if I can find them. In particular one to navy flight magazines from the war years. First I've got to remember the name of the magazine.
Here is one link that might be of interest
http://archives.aths.org/archives/default.aspx?aid=5 , had you found this one? Has 3475 Autocar photos
Cheers Phil