10 in drums

I am looking for a set of rear 10 in drums for my Formula S. Found a supplier yesterday who assurd me they had them in stock. After being charged they sent me a message they had no stock.
Any Ideas?
I had been told a set from a early 70's duster would fit. They are very tight on new shoes. I can get them on but can barely turn the wheel.

Have you checked the star adjuster on the brake shoes, to make certain it is
screwed together all the way? I have seen a few times, that brake shoe linings are sometimes a little thicker than usual (different manufacturers) which will cause issues with the drum wanting to fit over the shoes. Check that adjuster! Hope this helps.