date code for my A-833

My '64 came from the factory with a Hurst Competition Plus shifter. It's stamped into the side of the shifter tower. The trans came with the 4.35" diameter IBR. Not sure when they went to the larger diameter but I think it was when they went to big blocks. I would think if you have an A body trans with a 4.80" IBR it would be from a 1967 or later big block. IF the shifter is original it would be from sometime in 68 or later as mentioned by 67valiant. I don't know how to decode the numbers on the trans. I should learn, it can't be difficult.