Unusual Engine Colors

I read through all of the posts. I didn't find the answer to the on-going question at shows. Why did Chrysler paint some engines orange and some blue? Some people say it was where the car was built. Some say it was, as someone noted, the engine block/displacement. Having grown up during those years and having ordered a '69 Dart GTS with a 383 from the factory (engine was orange), and remembering that some cars with 383s had a blue engine, the question remains unanswered. Of course, the next question, which has no answer I could find, is whether or not the VIN has that coded like nearly everything else?