I believe that if you hunt around a bit and sort out the various disc brake knuckles of the era - you'll find that the Mustang (71-73), Maverick, Comet parts are just like the later Granada / Monarch pieces. The difference being the tie rod holes - the lower ball joint pin tapers are the same as the Granada. They are are often
sold as the same part, raised spindle height is close to the same (lowers the car), strength is the same, etc. It's the reason this discrepency comes to light every so often.
There are Mustang (and other Ford model) rotors with 11.19 OD discs - a bit more grip than the Granada - but gathering all of the proper matching calipers and bracketry can be a pain - unless you strip the donor yourself.
Steve Metzger Tucson, Arizona