Chevy only, calender 57[Jan 1 - Dec 31, 1957, which would exclude early 57 production in late 56 and include early 58 production in late 57] = 198,538 with GVW of 6,000# or less .... and that's prolly as close as you'll find, I don't think they started tracking details until late 60's ...... for GMC
might try oldGMCtrucks.com
Bill
