think i just found out why mine is 20 inch longer than the rest
Long Wheelbase Jeeps
The long-wheelbase CJ-3BL is not commonly seen in Australia today, and it is unclear how many of the 1000 3B's listed in the records from the factory had the longer frame. Chris Waters saw this nice example in September 2008 at a Jeep Jamboree. It is unlikely that the longer frame was part of any of the CKD CJ-3B kits shipped from Willys in Toledo, who never built an LWB version for the domestic U.S. market.
Vaughn Becker comments, "My son has a CJ-3BL which is the same as the short wheelbase with 20" added into the chassis and body. I have only seen one other." See also a photo of the frame (80K JPEG).
here is the link, halfway down the page
http://www.film.queensu.ca/CJ3B/World/Australia.html