My final Update as I figured it out for my tribute car
12/14/2024
Here is what I have: backing plates # 3209029/3209028 (Bendix). I have no idea what Fomoco product it is off as I bought them about 6 years ago on Ebay. A U tube video suggested to use backing plates from an 85' Full size Ford.
The usual refrain is to use Ranger rear drums, but those leave a 1/8" gap between the backing plate and the drum. Not going to work.
I ran into a U tube video and the person said to close the gap, buy rear drums that are from a 69 Cyclone with a 428.
These are part number 1639R (Raybestos). Rock Auto had these and yes, the gap is closed and fits correctly. So, there you go, this is what works. BUT: seems these drums are about 3 pounds heavier than the Ranger drums. At least you get the larger swept braking area. Go figure: it's 3/4" wider times 10" Pi.
Small issue with the drum. Just like on the Ranger drum, there are raised cooling fins along the entire perimeter of the Cyclone drum.
Hint: also seems that the brake combi kit (that's the return and hold down springs folks) come with the pins that hold down the shoes are a little short. The correct pin length for the 2 1/2" shoe is 2 15/32". You can order those at the local O'reilly's.
Had a conversation with a popular East Coast parts supplier. They informed me that the people who were stamping the backing plates for them went out of business. They were looking for a new supplier.