Donald D,
You haved made your entry with a time-honored question. Here is a pretty good compilation of Chevy engine colors:
http://www.danroy.com/ Go to this link and scroll down to Tailgate eTalk.
My bet is that 1954 and newer car 235 engines were blue (of "Blue Flame 6" fame) and truck 235 engines were gray (but the 1960 and upwards 235 trucks' supposed blue-gray color is real pretty).
My guess is that the bell housing and transmission were "natural".
This topic is a lot like religion - it takes faith to truly believe what you think you know (and, be careful questionning other peoples' faith).
Tim
