Modern 3 point seat belts?

Will these fit my dodge demon
I just last week had my factory belts shortened by 4 inches at an upholstery shop. They are much better now (lap belt stays around my hips instead of my belly). Again, my Swinger is a 1974. The belts were changing just about every year in those days, so my experience may only be relevant if you have a 1974 with bench seat.