Seems like May 17 1967. If you pull the cover off, the ring gear will have the ratio and date stamped. Could be a posi! I mis-stated 2WD 6 lug. 2WD 6 lug up thru 70. 2WD switched to 5 lug Disc brakes in 71. 1967 rear end does compute with all indicators. The date code helps too
