Although it has been a long while , this topic has been hashed over before. Some aftermarket 3 point belt retractors do interfere with a-body seat travel. Those earlier discussions included fabricating a part to bolt into factory hole(s) that has hole(s) to reposition the aftermarket retractor further back. Strength of the added part? How to prevent its pivoting? Cutting and welding inside the quarter rail? etc...
From what I gather, some brands/designs fit better than others in a-body. Which a-body will make a difference too. What fits/works in 68 Dart may not work so good in 73 Duster.
