Confirmed yesterday. As others have found Crager SS with the 5 on 5-1/2" pattern will not fit the 73-79 F100/F150 disc front end without the use of a 1" spacer......
Well, with "my" rotors that I had the hub center turned down, and redrilled to 5 on 4-3/4" They fit no problem...
to bad there was no interest as I had a shop set up to machine the rotors.... oh well......