My guess is gray ('52, 216) and gray ('54 235). Expect to get all sorts of answers. Nonetheless, Chevrolet colored drawings and technical manuals show or state gray as the truck engine colors for these years. That is, except for sedan delivery (panel wagon)in 1954, which used the Blue Flame Six 235 (which was, of course, painted blue).
Chevy Duty sells a blue (incorrect) for 1954 235 truck engine. Jim Carter seems to sell the correct color.
Here is one of many earlier discussions on this matter.
http://www.stovebolt.com/bboard/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=2&t=002149&p= Tim
