Hey DOM, here are some pictures of the C4 tranny as promised. Hopefully you can id these part numbers and cross reference to it's exact application. I'll be curious to know what you find in your research.
Thanks for taking the time to post those pics Hipo giddyup, I appreciate it.
From looking at the casting numbers and date stamps I've come up with the following:
Case plate C40P-7D027-A and date stamp looks to be 12/64 (December 1964)
Case C5AP-7006 B and date stamp looks to be 11/64 (November 1964) I also see a 23 there so combined with the month and year may be 11/23/64 (my assumption)
Ext Housing C4AP-7A040-C-(R or B), can't see any noticeable date stamp
So IMO this C4 would be suited for a 65 with a scheduled build date from 12/64 to 02/65