Rear “clip” in wheel cylinders. Why on earth did they do that - when a standardized backing plate with bolt in cylinder had been on the shelf - for what ? Fifteen years?? Guess the bolt in style can be swapped over
The almighty dollar my friend. They could save a couple of cents per car by going with a lighter/simpler/cheaper method thereby increasing profits. Department inter communication at GM was still in its infancy and part sharing was still taboo.
Get used to it, you’re gonna find things like that quite a bit on our cars.