switching from 68 to 73 will it work

The center link, pitman, and idler all must fit together, and of course in the case of the idler, it must also fit the K, such as in my case, I changed the 67 "one year only" K rather than modding it, because I had one with spool mounts as well.

Here

http://www.forabodiesonly.com/mopar/showthread.php?t=236925