1970 dodge dart seatbelts

A-body belts (at least the shoulder harnesses) are a little shorter than the B-body belts. They are also constructed slightly different from what this e-bay link shows. For a shoulder harness car, the front seat lap belts consist of actually two belts sewn together. They bolt together on the floor under the same bolt which provides a longer portion for your lap belt, and a shorter portion for the shoulder harness to cross and attach to. That shoulder harness has the buckle attached so you can adjust how much slack you have in the shoulder harness.
You can see the short piece attached to the longer lap belt in this photo. The buckle in this picture for the lap belt is hanging over the front of the seat attached to the plastic storage clip.


And the back seat.