I was able to determine that by the block number, my 235 is from 1955-57.(3837004) However, what is stamped on the pad behind the distributor is confusing.

Here is a pic:

http://s36.photobucket.com/user/riverwork/media/Chevy49/Ser/Serial.jpg.html

Reads across the top:MRC45439, then the line below is:031559Z F56Z