Re: 1972 ford thunderbird brake rotor
72 fullsize cars use a different spindle with a different caliper location. 72 Thunderbird uses the same spindle as a 72 Torino. Torino rotor is smaller, difference is made up in the caliper mounting bracket.
72 Torino/Thunderbird use a different bearing set than 73 and up Torino/Thunderbird. So, you have a one-year-only rotor, as in 73, Thunderbord started using a bigger bolt pattern for the wheels.
If you are working on a 73 and up Torino, you can use the Thunderbird/Fullsize rotors with a 73 up Thunderbird/Fullsize Caliper mounting bracket.
You will have the big rotor with the big bolt pattern. You can get the rotor redrilled for the small pattern or find/install rear axleshafts/drums from a 73-76 Thunderbird or Mark IV with rear drums and use large pattern wheels.