There is a metal "disc-like" thing that was supposed to be spot-welded to the upper part of the shock tower, but I've never seen it come out. There was then applied to the top of the coil spring a rubber bushing to insulate the spring from the upper tower (this disc-like thing) - and that should be replaced too. Do the lower spring perches as well. They are inexpensive (thank you Mustang for using the same one) and are a wear part - and also the leading cause of the "Ford Squeak". These are also available with true roller bearing pivot instead of the rubber interface pivot - for a slight premium. I think Patrick has these in his Falcon and recommends them.

Can you take a photo?