I put lap belts in my 46. I bolted them to the floor through the holes behind the seat. I used all grade 8 bolts and 1.5 by 1.5 by 0.25 in. Angle iron. I think the goal is not to get ejected. I don't think there is enough structural strength for a shoulder strap even with steel plates added. If I wanted a shoulder strap I would weld in a 1/4 inch angle as long as possible inside the space in the upper cab wall and door frame. I have photos in photo bucket of my floor mounted system.the floor is reinforced as part of the OEM design in this location.
