You can at least measure the inside diameter of the drum from inside the wheel.
IIRC, the 14bff has three brake options, the small (~11") , the large (~13") SRW, and the DRW (also 13", but 3.5" wide shoes instead of 2.5".)
The small size is about the same diameter as a 10- or 12- bolt rear, but has different width shoes.
I still don't recommend it, but if you only have the one vehicle and can't take it apart, then drive to the parts house ... maybe.
-- A