For additional context on the 727s, you'll find two sets of numbers on the driver's side of the housing, just above the pan. One is the part number. On the pre-1968 transmissions, there is a second 7-digit number and that is NOT a date code as you'll find many people stating. Date coding, an 8-digit number, started in 1968. From 1962 to 1967, it was a 7-digit sequence number that you can ballpark the date of based on where it falls in line with the series and other transmissions. The only date coding on the earlier transmissions are the cast markings higher up on the body of the transmission.