Metal reinforcing plate welded to the center of the rear body, where the 9 inch third member may come into contact with the floor. Cut from one of our many parts cars. Likely originally had a Ford part number of 4731. Removed from a 1971-73 Mercury Cougar, we suspect that it will not be a direct fit for a Mustang.
This part will come as shown, spot welds will need to be drilled and the plate welded to your chassis.