The T shifter in my '65 Coupe is loose in the floor console. The '72 FB I had also had the T shifter in the floor, but it was tight. Any reason the stick would be wiggling?

 

I assume that you are refering to the shifter for an automatic?

If so the bushings in the shift linkage are gone. Very inexpensive and relatively easy to replace. Go to your favorite mustang store and search for shifter bushings. I think the ones I bought were less than $5.00