Adding these for easy reference. Even though the site I found this is a
chevelle site, much of the info seems to apply to our trucks.
Tyler, I updated two serial numbers as a result of the info below: 01121369 & 0F128831.
68 chevy
8S215655 = 07/03/68 - 07/31/68 (post 311)
72 chevy
21158907 = 06/14/72 - 06/16/72 (post 311) This was already on the list, but better picture and more detail this time.