[Jim Doran]

http://www.keislerauto.com/gm/transm...lle_64-67.html

Tech note: THE NEED FOR TUNNEL REVISION – Keisler Engineering makes every effort from a design standpoint to allow the use of the PerfectFit™ System with no tunnel modifications. On some cars, such as the GM A-body, there is no way to achieve the correct driveline angle in the original tunnel. In cases where tunnel mods must be made, the original carpet, console and shift position are retained after the provided sheet metal is installed, making the installation as clean as possible while giving the proper mechanical result.