Welcome!
Here's another place that could help you,
Big Horse Parts & Restorations The guy deals with the 71-73s strictly. Good guy and he has redone cars for himself too so he knows them. He'll know who I am too if he saw my user name on here.
National Parts Depot (NPD)
NPDLink | National Parts Depot and Mustang's Unlimited two of the big Mustang parts suppliers that I recommend. I have spent thousands with both of them the last 10 years and they have been very good and I've even gone to the MU store here in CT several times.
The parts demand for the big 71-73 cars is expanding more rapidly the last few years as more people are getting interested in them. The restoration of these cars is becoming easier now although you'll find they are still behind when it comes to the earlier ones. It will slowly get easier (and cheaper

) though as more repro parts are brought out for these cars.
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1968 Mustang coupe, Acapulco Blue, 289 2v, C-4, Power Steering.
Hopefully a 1969 convertible or Sportsroof (non Mach or Boss) for next Mustang project
Trying to find my father's 1973 Mustang Grande he bought brand new. 3F04F126773 last known registration and title was in New Jersey, 1982.