71 vs 73 disc brakes

Use front clip off 71 car on your 73....sell 71 small bolt disc brakes(4 piston Kelsey hayes)....enjoy
There's no need to change the "front clip." You can put 73/ later disks on either a drum or early four piston car by changing the upper control arms (larger ball joints), spindles, lower ball joints, calipers and rotors of course and hoses. The later disks are large bolt patter, all of the early 4 piston ones are small bolt pattern