I have a 73 340 dart sport originally fitted with the fold down seat.
I dont recommend trying to finish the install unless all the brackets and the package tray have been modified/installed. It would be easier to install the original standard rear seat in my opinion.
Otherwise, if all the changes have been completed its pretty straight forward. There is carpet installed on the floor between the seat back and the trunk fold down between the wheel wells, and on the metal frame of the seat back as well. The carpet matches the color of the interior, black blue etc. The trunk fold down has this carpet on the face on the interior side. Install the package tray and facia trim. Next install the wheel well trim pieces (large plastic deals), there are screws that hold these on to the floor and to the back edge of the wheel wells, and several on the front near the door/window panels. Then install the trunk divider and latches. Next install the seat back frame hinges on the wheel wells, and attach the seat back, it slides on and is held in place with screws. Install the catches for the seat backs. INstall the seat bottom. Done. These instructions are from my memory so a step or two might be out of synch, so use logic when installing.
If it were my car I'd return it to a standard back seat. You get alot of road noise from this set up. The car will be quieter with the standard back seat.
