If anyone cares here's an example of one of the unique Canadian Suffixes as mentioned above..
This one is from a Canadian built and GM Vintage documented '68 SS427 Coupe L36/Stick car..
Not that it has anything to do w/ the Suffix code but yes it's a Z24 equipped SS427 car, not an Impala SS w/ a 427..
Engine stamping # T12143T
Obviously Tonawanda Dec. 14'th '67
Suffix 3T = Canadian L36 Manual Trans
~ Pete