I have repopped these John Deere snowmobile tunnel stiffner reinforcment kit for the rear near the grab bar.  The original JD part number was AM54705 and was for the 76-78 cyclone and liquifire snowmobiles.  For in instructions on how to install click the link http://www.jdsleds.com/tech/instructions/tunnelreinforcement.pdf .   There are left and rights included as well as stainless steel rivets.  The black one in the picture is the oem john deere one and the bare aluminum are the ones I have made.  Please send me a message with any questions.