[1960HDGMC]

Here is a method of deciphering the code stamped on the speakers of the 1960 GMC trucks. It may likely work for later models. I will use my speaker in hand for an example. It is stamped "466938". This is the Speaker Code. The first three digits (466) represent the maker(in this case ,Delco). The next digit is the year in the decade(in this case,1959). the last two digits are the Julian week code(number of the week in the year),in this case, the 38th week of the year. Delco made this particular speaker in the 38th week (second week in September) of 1959. If you have a factory speaker in a GMC Radio from 1960-66,you should see a 6 digit number that begins with 466, and is followed by a year in decade number of 9,0,1,2,3,4,5or6. The last 2 digits will by default be between 01(first week of January) and 52(last week of December),the number of weeks in a year. So one can extrapolate that the Delco factory speakers in our 1960-66 trucks will have Maker Codes stamped within the range of 466901 at the earliest and 466652 at the latest. This range is not set in stone, but should used as a relatively complete guide to factory maker codes. The code is ink stamped on the bottom of the speaker on my example. They may have moved the stamp to the edge of the speaker frame at some point. Just look all over the back of the speaker you have ,for a number that has 6 digits, starting with 466. Happy Huntin, Greg Mead