Dave, the more I dig into the car the more evidence of "a$$-monkery" I find. Part of the fun, I guess!
I just measured the shoes off the car using calipers lining edge to lining edge, and they are almost exactly 2 1/2. They do look a bit bigger in the pictures, though.
I wonder if those are rear shoes that for some reason ended up in the front? Don't know how to tell the difference on a C-body. Also I think there are two trailing shoes on the other side, another piece of evidence of not so skilled maintenance in the past. Now I'm super paranoid, and will tear into the rear brakes as soon as I'm done with the front whenever that will be. The car is out in the driveway since I figured this would be an afternoon's work, and I want to button her up before moving on to the next task. Best laid plans...
A number of things are possible. Given that some nimrod installed the front shoes *** backwards, I would suggest pulling a rear drum to see what size shoe is on the back brakes. Brake shoes on the rear are generally narrower than on the front by design as the front brakes do the majority of the braking. If you have 2 1/2" shoes on the rear most likely you would have had 2.75" or 3" shoes on the front from the factory. If you have 2" shoes on the back, things start to get more interesting.
I have a '65 Chrysler Newport with 2 1/2" brakes on the front and 2" shoes on the rear and it is an unmolested car with 45K showing on the clock. So how does this happen. Known in Mopar as a "Production Variance". Not sure if that means that they ran out of the right parts or whatever. I know that being a Mopar tech in the '70's and early 80's that stuff like this does happen, and they used to drive us nuts. Books shows one thing, what is on the car is not what the book says should be on the car. So go figure.
Dave