Parts application and ID help

[69L72RS]

I have two parts that I need help identifying.
The first is 3936446.
The second is a r&p set 3916230 & 3916231 dated 4 of 69.
Thanks in advance for any help that you can offer.
Eric

[Nova Research Project]

69L72RS;

I found 3936446 replaced 3887370 5-69. 3887370 replaced 3863421 3-66.

3936446 lists as CASE, Differential and Planet, for a 65-69 Pass., 70 Chevelle, Camaro (P/Trac, w/4.10 ratio) . w/4.10, 4.56, 4.88 ratio (Eaton 12666-8) (Note 2) ...
NOTE 2 Use with 12 bolt cover.

I did not find 3916230 or 3916231 in the 1962-1970 Part and accessories catalog or parts history.

[69L72RS]

The 3916230/3916231 are ring/pinion part numbers
with a 9 & 41 tooth count and a date of 4-69. It is a 4.56 ratio set. The part numbers are sequenced with the COPO 4.10 r&p set 3916226/3916228 and the standard 4.56 sets that I have end in 515/527 part numbers. I believe that it is a COPO 4.56 r&p set, but can't find it in my books because they aren't old enough.
Thanks for any help that you can offer.
Eric