Brake question on 72 dart

Like I said brakes were out. Know of anyone selling a booster like this one. Master cylinders no problem.

When building our 70 Dart we had to send our booster out for overhaul. I ordered one from Partsgeek and it was bad on arrival. I would see if there is a local shop that can rebuild what you have.
Here is the link to who we used:
Welcome to Karps Brake Service

They have been around forever and took care of us.
Good Luck.