This is interesting ... but ...
Since this post is primarily about a "model" of a 37/38 truck, and not an actual truck, suggest this post be moved to the Spoon and a note posted to the "Moderated" new poster about the change.
Admittedly, I had to go back and check and then saw it was a model truck
We had another request last week about some discussion on "earlier trucks" and have been contemplating that request. I mistakenly thought this was similar to that one and that initial request bumped up one notch.
But ... on this one ... not the same. Gonna move to the Spoon and I'll alert the OP ... Maybe he got what he needed from all the suggestions and he's hard at work on his model truck!
Maybe he'll post a picture or two of his work or what he ended up with.