I believe this is the worst case of butchering a chassis C notch on any truck that I have ever seen.
Apart from the total lack of chassis integrity beginning at the forward most part of the cut, the shocks have been pounded on by the chassis edge, making the shocks most likely ineffective, plus angle is just WRONG.
The "reinforcement" plates someone mentioned is doing zero to strengthen the chassis, as the center of the arch is now simply a flat plate, rather than a C channel section.
I believe the only way to correct this is to recreate the side member of the chassis, down to the limit of the notch kits currently available...the outer edge of the current notch piece will need to be cut back to permit the flush mounting and full perimeter weld of the new notch kit.
Once the new kit is in place, a new fish plate style reinforcement plate should be placed on both inner and outer areas of the notch area.
It may actually be simpler to Z cut a new rear chassis section beginning at center cross member, then perform a standard C notch kit install...
Shock relocation and adjustable track bar as standard needs...
UGH UGH UGH

