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.
Also added new master cylinder and brake lines with wheel cylinders. No fluid in cylinder yet.