Looking at the 50+ YO passenger seat's belt in my old car and wondering if it's "safe" at this point. The shoulder strap is long gone since it wasn't reinstalled after the headliner was replaced before the roll bar was put in... now it's just a factory '73 lap belt.

Since I need to get an updated 5-point for the driver's seat, I'm wondering if I should get a second harness and add one for the passenger. I'm interested in what approach others have taken. Thx

I always used old outdated belts for the pass seat, new ones (dated) for the driver seat. You can find plenty of old outdated ones out there for free or real cheap

I just took a set of blue RCI camlocks out of my car. They're yours for the shipping price if you want.

55 year old lap belt on the passenger side for a long time now, but now that I'm in "restoration"/huge improvement mode
will probably update the bar and add a couple tabs to allow a bolt in harness, some old guy swing out bars and things like that.

FWIW - and I do this myself - expired 5-point harnesses can be sent back to the mfr for re-webbing and re-certification.
Been doing that with my RCI cam-loc harnesses for years.
It's a fraction of the cost of new ones.

In addition to the old harness in the car, I have a new harness sitting in the original package that expired before I managed to use it. For RJS, it ends up being about $100 to have them re-certify it by the time shipping both ways is factored in. However, I'm going to change from bolt-in to wrap-around shoulder straps and this requires buying a new harness anyway.

When I put the 10 pt. cage in my cuda, I put the same style 5 point harness on both sides of the car. It has the factory bucket seats from a '73 Challenger in it.