The pick up points on the rear trailing arms were moved on the body. 84-85 only. The bracket lowers the frt of the arm approx 1 inch. Wrong direction when lowering the car. The tubs were 2 pieces of sheet metal thick at the rear upper pickups with a brace on the floor in 79-80 chassis. Later chassis are three pieces thick at that point which is why later cars rust out more at the seat belt mounts. Lots of places for moisture to sit. I dont tghink the a pillars were as thick early on either and sunroof frames/brackets are on all chassis after 81 weather it has one or not. Stupid things you learn when stripping cars for the scrap yards.