1973 Plymouth Valiant Drum Brakes Issues
I think you have WAY more troubles than "adjusting" the brakes "at minimum"
PHOTOS of the damage are nearly going to be mandatory, here
You have a service manual? There is no excuse. They are free and are WHAT YOU NEED if you are going to do anything at all with these cars.
you can download them here:
http://www.forabodiesonly.com/mopar/showthread.php?p=1970088617
http://www.mymopar.com/index.php?pid=31
What you are screwing with here is the potentially most important, life threatening systme on your car, except maybe, for the steering. Please think about that