I just picked up the Revell/Monogram 1937 Ford Delivery Truck, and it seems like a nice kit. The instructions say to paint the engine a "medium green", and a quick Yahoo! search has verified that Ford did indeed paint their engines green in 1937.
Now, my question is, what is a good match for the 1937 Ford Engine Green? The only reference pics I've really been able to find are either pics of engines that some has hot-rodded, or black & white photos. Neither of which are terribly helpful.