retractable seatbelts in narrow cab/pre 48

[kendall]

Anyone install 3-point retractable seat belts in the pre 48 dodge pick up? I ordered them after creating a paper scale model of the retractor and determining that they 'more than likely' will work! Caveat; there can be no rubbing of the belt against the seat and cab, the hanger must be mounted directly above the retractor with the belt at a perfect 90 degrees, parallel, and swivel to boot! And of course all 3 points of attachment to the truck to be a rock solid/ grade 8  connection, preferably through the frame. Keeping my cardboard interior liner would have been impossible so out came the mat knife. The photos show what lies beneath. Take-away 1; The retractor will have to mount vertically above the filler tube, a manufacturer no-no. Take-away #2; the hanger will have to be placed about halfway between the two horizontal beams or about 8" =/- above the seatback. Take-away #3: Any steel framing I install should not become a weapon to stab or clobber me in an accident.

[Plymouthy Adams]

you do not wish to mount to the frame...in a very serious accident the human body should remain intact with the vehicle body and let the mass weight of the frame and drivetrain take its own directional movement...

[kendall]

Good to know,makes sense to not fasten yourself to the component that will acquire the most abrupt trauma, the only problem is finding ample resistance in what is mostly sheetmetal to prevent the fasteners from tearing out under extreme tension.The door  jamb where the upper hanger will mount appears to be maybe 26 ga. / two channels with welds spaced pretty far apart. If the upper hanger fails,I’m a dead man regardless of the bottom mounts success.The top mount is the challenge.

[Jeff Balazs]

I had a welder/fabricator buddy reinforce my Pilothouse cab specifically for seat belt mounts prior to paint. This probably doesn't help you........but maybe you could add some bolt in reinforcement plates?