I found some info in ebay that I would like to pass on.
Below is an exact reproduction of the pinion snubber floor reinforcement plate used on 70-71 Hemi powered E-body Mopars. (That´s what the seller claims).
This is an exact reproduction of the spring hanger reinforcement plates used on 70-71 Hemi powered E-body Mopars. These have also been seen on some 440 convertibles as well. This is for the 4 flat plates only, not the torque boxes! (That is what the seller claims)