I'd like to replace the seat/shoulder belt system in my 1973 El Camino with up-to-date equipment that has only one latch instead of the "hook the shoulder belt to the seat belt and then attach the seat belt to the anchor", but need to know: 1. If there is such an update system and . . . 2. Where can I get such if available? I see in JC Whitney that there is a universal type but don't know if it will work in my car. They don't either.