I spent an hour or so looking thru the brake rotor book at the parts store and found a 12"x1" rotor with a 5 on 5" bolt pattern for $40 a piece. And they were in stock. I am adding the rear disks to the 72 GMC. The rotors will have to have the center hole bored to 3" and the od turned to 11.5". But hey, I am a machinist by trade so I can do that in my sleep.