Hate to break this to you, but with that serial number its just a bit older that late 50s/early 60s. Model 22-40 was made from 1919 to 1925, but the serial numbers don't match up. Take a look at
this URL http://www.ytmag.com/cgi-bin/snlookup.cgi?mf=CASE
This site gives a wealth of information on all kinds of old tractors, and if you are of a mind to start a restoration project, the Case site on Yesterday's Tractors discussion forum is a wealth of information at your finger tips. These guys are all Case enthusisists and are extremely helpful!!