Mid 1970's Monte Carlos used an 11X2 rear drum set-up--that's what MPBrakes uses for their 11" conversion kits (with all new parts, no recycled components)
http://www.mpbrakes.com/1968-chevrol...0legend&page=3
I have this system on the back of my Chevelle. With (manual) OE disc brakes up front, it hauls down my 4000+ lb. heap from 115+ mph @ the track with ease.