what is the body part strip under the back window? before the trunk starts?
It's called a "upper body panel". GM discontiued it a long time ago. 81-87 Regal 2dr will work. Be carefull on removal, it's uses plastic clips on the forward edge to hold it. If removed correctly you will not break these.
Phil
Howard, Paul, correct me if I am wrong on this, but the panel is interchangeable between all 81-87 "g"body vehicles(i.e.,regal, cutlass, monte, etc.) -Robert