The normal power front disc brake cars all had 11x2.5" rear shoes. An upgrade from there would be the rear brakes from a HD Drum Brake car, which would be 11x3" rear brakes. So check the width of your current rear brake shoes. The unfortunate thing is that you'll need to find a rear axle with the size of brakes you need and get ALL of the parts, including the backing plates.
If you are of an age demographic which grew up when everything had rear disc brakes, consider that the OEMs made the switch more for ease of assy line assembly, reduced labor to put them on the cars, and that they could get more performance from lighter components (which is a factor in EPA fuel economy ratings). Although fade resistance is an attribute to disc brakes, most drivers do not get anywhere near the limits in that area, by observation.
The other consideration is the supply of new, quality brake drums in the future. To me, this could be a compelling reason in itself, if the car will be driven daily for many more years. If only 3-5K miles/year, not so much, unless this will be your "forever car". Brake drums are "consumables" which can't be reused past a certain wear point. With sales of such decreasing as a natural part of things, it's easy to see where that road will end sometime in the future. One reason for it not to end is that 11x3" and 11x2.5" rear drum brakes were also on many E and B-body muscle cars, which ALSO can command 6-digit prices at auctions when completely correct, as produced, cars.
Enjoy!
CBODY67
