Hy Laurence and guys, I looked up the V.I.N./serial number in a 1962-71 medium duty parts book, while there are some "errors" in that number here is what i was able to determine
T = Tilt cab
S = six cylinder gas engine
4 = series 400-450
37 = normally the cab to axle code, however these digits do not correspond to any in the code record, code numbers for Chev. range from 06 - 31, GMC range from 56 - 81
P1 = body and brake type code, note there are no letters in this code, the code numbers range from 02 - 62, this truck would most likely be an 03 = cab w/o air brakes
the remainder is the regular production number.
Hope that helps.
