According to What I can find, that is a 1940-1953 U joint. 1933 to 1939 are "open" drive shaft and the U joint looks more like a modern one. So I looked at the manual...and it looks like a torque tube to me. http://chevy.oldcarmanualproject.com/shop/1938/38csm086.html
And that would be just like what you have in the picture. So further looking got me to here: http://www.vapinc.com/chevy/Universal%20Joints%20and%20Parts/main.html I think this is the folks that make the parts every one is selling. Might be worth a call for more information.
Some one here will know what I am guessing. I hope you get some better information than I was able to find.


Steve H