I came across a M21? with coarse spline single groove shaft. Stamped P0827 along with 5Z118585. Case casting number is 3851325. Tail stock # 3857584. Is this a mid 60s muncie? Also is the 5Z118585 part of the original cars vin? Any help is appreciated. Thanks
John

Try this:

http://www.5speeds.com/muncie2.htm

It should answer most of your questions. The main site also has other information, rebuild kits and videos etc.

Thanks Red. A very informative link.
All my questions are answered
John