Factory engine painting video
 

This was discussed before, but then the video got deleted. They added it again.
This film (it says 1956, but the final footage is of a 59, so it's probably closer to 59) has shots of the engine being painted.
https://www.youtube.com/watch?v=dmwdFTyMmiQ&t=684s
The automotive part starts about 16:25. Lots of interesting shots including blocks, cams, frame rails, etc.
17:50 - inspector stamp on the block
19:40 - block painting, including painting three different color blocks.
23:30 - How about that frame? The complete exhaust system is painted!

Thanks for finding this again Kurt.

I have a collection of Chevrolet and GM videos. One of the most instructive as to the level of embellishment is the proving ground video where the upper and lower control arms are painted different colors including red.