Here is an FYI on torsion bars for 67-73 Imperials on e-bay #2535512 & 2535513.
http://cgi.ebay.com/ebaymotors/2-Used-Chrysler-Imperial-Torsion-Bars-2535512-2535513_W0QQitemZ150060329656QQihZ005QQcategoryZ34200QQrdZ1QQcmdZViewItem
The broadcast sheet on my 69 LeBaron 2 door calls for #517 left and #516 right presumably because it has the towing option.
Fred Joslin