Google speedometer repair in Portland, OR, there are two shops that do that.
I can't remember the name of the shop I used for my 1966 Dodge Coronet that had set for 27 years and was frozen up, they repair it and offer to restore it but I didn't want the speedometer done with all the other gauges stock so I had them fix the transmission part only and not restore the face
There are several other companies that repair and restore old car and old race gauges out here on the west coast but I have only used the one in Portland.
Does your Cuda have the standard gauges with the 120 MPH speedo or the Hi Po type with the 160 MPH speedo?