1966 valiant rear brake shoe removal?

I've always just used a good big pair of pliers--slip joint--Grab the outer cup with the pliers so you can apply inward pressure, and reach around behind and hold the stud "out" against the backing plate. Plus in, give it a 1/4 turn in either direction and it should come right off

As old as "these girls are" you should replace those if you can get them...likely rusty and weakened.
That’s the way I do it on my dart but these are designed different. It’s con-ish style spring the skinny side goes through the shoe and hooks to a stud that’s pushed through the backing plate. The kind you are talking about is a uniform spring with a cap on it and it’s pushed down onto a long skinny stud I believe.