IN the Chevy trks 47-54 I've used Camaro & G body clips(78-88). The G body's clips are approx 3" narrower,thus are the same track as the original trk.
Thus, if your current track is aroung 58" you might consider the G body clip.Here are some more pictures
http://71.65.63.136/web/photos/default.aspx
Don