And I implied a question, which he (and you) have not answered so I will ask again explicitly:
If the seat and the driver are moving forward, and the belt is not (because it is fastened securely to the body), why does the belt not become tighter?
It will become tighter when moving forward as long as it is secured correctly and doesn't rip out of the floor. But if you bounce off a wall or guardrail and end up going backwards it will become real loose. It's also very possible to back it into a wall or object during an incident.
With that said, my Duster has 3" lap belts just bolted to the floor with large washers. I need to decide on a factory shoulder harness or something else. This is my first street only build, I'm use to having a 5-way harness mounted to a roll cage.
