Neil, there are a lot of differences, some subtle and some significant. Length is probably the biggest concern with this swap, the 60's beds being a lot longer than your 55 bed. Of course there are two different bed designs within the 60-66 series and it depends whether you have the 60-62 or 63-66 bed. We have detailed the major changes in our "Bed side interchangeability" article under http://www.mar-k.com/installation_hints.html. Scroll down to the Bedside interchangeability for long beds for more information.

Mar-Ktech