I think I have made a howler

in my article on the origin of CMPs in VINTAGE ROADSCENE magazine which is about to conclude by the way with part 13.
I need to clarify what differences there were between the C15A/F15A transfer cases and other CMPs please. I found this old thread of mine:
http://www.mapleleafup.org/forums/sh...=transfer+case
Basically, which chasiss had single-speed and which two-speed cases please? Also I am sure that the 15-cwt 4x4 cases differed from other CMPs?