I have been collecting parts for a 67 Build for over 30 plus years while digging in my basement wanted to verify this transmission. any help greatly appreciated. no other stamping on the transmission
case # 3925661
tail shaft #3978764
cover #335308
Thanks #ad

 

Thanks again for the invite

 

An M22 gearbox has a 20 degree helix angle on the gearset as opposed to a 45 degree angle

 

https://www.ss396.com/cars/complete...to identify,not necessarily the calendar year.
here is a link that might help