If you can find a big-body mid-80s Ford in a junkyard, you can take the backing plates and everything else and have upgraded, 10 x 2-1/2" rear drums. They will bolt right on. I did this with my fastback. Used the OEM wheel cylinders so I didn't have to re-bend the brake lines, everything else came off an '85 Ford Crown Victoria (IIRC).
In case it helps...
"When a woman is a really good driver, she is just about perfect."
- Raymond Chandler
'66 GT Fastback show car, nightmist blue, warmed up original 289 & T-5Z, 3.80 trac-loc, AC, PS, pony interior, Retrosound, rally pac
'66 Coupe driver, Bullitt green, 302HO w/ 351W heads, roller rockers, Holley 600, T-5Z, 3.55 trac-loc, collapsible column, tank armor, disk brakes, shoulder belts
'11 BMW 335i X-drive, 6 speed manual, all the bells and whistles