Factory they were mounted front. It's possible to swap the spindles side for side, and install them to the rear. This is an advantage in some cases, for anti-sway bar clearance. Disk project or "Thank Gauwd fer power tools" LOL
So far as I know, the only downside is that factory hoses won't fit. I used Volare hoses on mine. You must be careful to get the bleeders UP!! UP!! Bleeders UP!! LOL