what year 904 trans is this?

hi guys,
i was wondering if you could help me figure out what year and motor this 904 transmission came from? the number is 2466871 and another is 3515394.

From what I understand the 2466871 number is from 1964, the 2 means the decade of the 60's. The 4 is the year of the decade. The rest are what kind of part it is and build dates. 1964 is when this part was first used.
This works till 1971, when for some reason they skipped numbers. In 1971 the part numbers started with 3, decade of the 70's, but jumped to 5 for the year number.
Sounds like you have a trans that was redesigned in 1971.