['72 Cheyenne Super]

A 2" guage fits nicely behind the clear lense (if you remove the bezel). I mounted a Stewart Warner 90 deg. sweep trans pressure gauge in that same location. If you're very careful, you can remove the paint "crown" from the backside of the lense with a modeling knife (carefully scrape it). I removed the bezel, and after I cut the sheetmetal in the back of the cluster to mount the gauge, it fit snug up against the lense. (Sorry, I don't have any pics at this point).