Which way do the calipers go?

The calipers can go to the front or the rear, the spindles can be swapped side to side. All you have to do is make sure the bleeders are on the top and the brake lines are long enough if you put them in the back.

The 73-76 calipers were in the front from the factory. If your ‘72 has a front sway bar you might want to mount them to the rear though, because the 73+ brakes will interfere with the sway bar on 67-72 cars. If you put them to the rear, you need longer brake hoses.