... I have looked through here and it seems like 71-73 are nightmares. Thanks
The 71-73 are the older design. Thereafter the Pinto and Mustang II shared similar. I believe the springs are similar to all years and the Mustang II V-8 (or V-6) springs might work. Hopefully someone will confirm.
The rotors for the 71-73 are expensive (and not as good I've heard) as the later cars. I believe there is a mix/match with 74-up rotors and GM Metric calipers to the older cars. To confound things even more the '73 Pinto's had a one year only steering rack!
Having done a '73 Turbo Swap I think I would have now bought a 74-75 car and just done the bumper body swap to make it look 71-73.