I'm sure all of the odometers are the same around that same era. I rolled my 59 Impala back. It took me about 15 minutes too figure it out and had it rolled back in about a minute. Lets see if I can explain this. I grabbed the gear end and spun it back until the first digit stopped. Then I flipped the first metal tang next to it the oposite direction. Then the next digit spins along with the first (the digits are lined up) until those stop and repeat the process. Getting the tangs to line up in the proper position once installed is a pain. Here is a pic of what an Impala looks like. I think I took this pic before I had all of that figured out.
