70 vs 71 Non-N42 Chrome Exhaust Tips rear valances.

The depth looks deeper in the 1970 valance. However, it is the same height. Reference the recess area for the lower mounting screw hole. The top of the round exhaust cutout are the same height.
Take a look at the bottom of the 71 valance. The bottom has been modified (by the factory) for the 71-74 models.
Apparently, in 1970, there was something about the rear leaf springs hitting/bending the bottom of the 1970 valance. So the factory modified it. Kind of like the hemi fenders...make it work.