Look on ring gear and sure grip parts.
When i was looking for a center section, i looked at dozens of them on ebay and the cast in ( what should be the date code) were all over the place with numbers and letters that could not work as a date.
Example assuming a letter was the month.... Some letters were too far in the alphabet even excluding "i" and "o" etc
Previous post where i i tried to make head or tail of it all:
