I remember posting about how vehicles were manufactured during World War Two and learning how they put chassis together with the engines and sprayed the whole shebang olive drab. I have a Model T 1915 ambulance model and wondered the same thing. What color would engine/chassis be?

Here's a 1917 Model T chassis :

http://modelersalliance.org/gallery/thumbnails.php?album=167

H.P.

When producing the Model T's Henry Ford is quoted saying, "You can have any color you want, as long as it's black".

I'm not understanding what you mean by assembling everything then painting it all OD. I have taken apart WWII Willys and Ford Jeeps, 1/2 ton and 3/4 ton Dodge and between parts, fenders, body, frame there was OD paint indicating the parts were pre painted before assembly. Some engine parts were typical Willys, Ford and Dodge colors, others black, a few OD and some bare metal.

I did talk to the night manager of the Willys Toledo final assembly hall and he said the last thing they would do before the military's final inspection was blast anything that needed a touch up with OD. As a result a Jeep could have several hues of OD.