if you mean the arm they are attached to, then yes. it uses the same upper and lower ball joints. the main thing you have to worry about is the brake lines and proportioning valve. i read in an old post that the lower arm from a 68-73 mustang is the same so i just ordered that and will let you know if needed (ball joints just are not as well made as they used to be)
Spindles from a 77 will fit a 73...You may have to use the 77 outer tie rod ends though on the 73.It all bolts right up.