New to the forum 73 Dart

I suppose that you know that the self-adjusting blade has to be pushed OFF, the star adjuster, and HELD OFF, BEFORE you try to turn the adjuster right? Which means that you need two tools in the window. Assuming yes you knew that;

There is a likely a ridge of unworn drum right on the edge of it, that is catching on the shoes. When it does this, the shoes tip over, and when that happens, they appear to the drum, to be longer/higher and the whole thing jams up.
But, before you get too cranky, disconnect the parking brake, cuz over the years, I have had many jobs where the parking brake cable had seized and is holding the shoes in a lightely applied position, which just makes everything jam up too! See note-1 below.
Next, check to be sure the drums are not seized to the axle registers. If they are, I find that smacking the drums where the 90* is, where the vertical side meats the horizontal outside of the friction area, usually breaks it loose. This may take multiple turns of the drum, and energetic pounding. This has to be dealt with first.
Then,
after the drum is loose on the register, and the Park cable is known to be relaxed, what has sometimes worked for me is to put a prybar between the drum and the backing plate, and try to gently pry the drum up and over the shoe, while simultaneously rapping on the opposite side of the drum, towards the screwdriver.
This is delicate work not pound the chit of it. All you want to do is get the lip of the drum up onto the shoe. and then, of course, you gotta get the other side up too, lol.
If at any time the drum comes off the axle register, then you can put a pair of heel-bars in there at 180*to eachother, and pry with those. I can usually get those bars in one hand and hammer-pound with the other.
When all else fails, see note -3


Note-1
Just cuz you disconnected the forward end of the parking cable, does not mean the parking brake is relaxed. The cable tends to seize inside the sheath, in the last few inches just before it enters the drum, or in any low-hanging spot or both. Sometimes, the cable has to be worked or sacrificed. If you have to cut it, do so right at the backing plate. If the cable was seized, there is a spring inside the drum that will try to relax the parking brake lever, If it is successful, and if the cable was the cause of your adventure, then the drum should now come right off. If the cable is not seized; stop! don't cut it. The cable is more expensive to replace than the drum. lol.
But, if the spring is not able to relax the adjuster, More likely, then you will need to find a steel rod about a foot long, and stick it in the hole where the cable was, then go find the park-lever inside the drum, and pound it towards the back of the car, which will solve that problem. That lever seldom gives trouble.
Note-2
If you cut the shoe retainer pins off, on the backside of the backing plates, Maybe you'll have better luck than I did. This will allow the shoes to roll over right away and jam up, plus now the adjuster area will tend to follow the drum, making things worse. It didn't work for me.
Note-3
here are three choices;
1) yes the drum puller
2) If the drum has to be saved, then, drill a window in the flange side of the drum and go find the adjuster, and if it is seized, cut it into two parts with a torch. This wo ill allow the shoes to collapse inward and badaboom yur all set. But you gotta figure out pretty close where to drill the hole.
3) if the drum is shot, you can just cut the friction areas in two or three places, but again, you gotta NOT cut where the shoe anchors are, and not where any important bits are. I have never had to go that far, but there are a few windowed drums of mine out there. If you drill the first window in the wrong place, well now you know where Not to drill. so just move 180* and try again.