one big thing to consider--the crush rate, ie deceleration, is very different between cars and trucks--that all affects belt stretch and belt lock up and a myriad of factors
I would not ride with those belts
that's my 2 cents
PS this forum group is notorious for defining minutiae of details in correct restoration, so I am using that same idea in describing this installation
in a way, you are saying "close enough" in regards for your safety, but I would not think many would use that term in restoration details
My comparison measurements between vehicles was for belt geometry & anchor placement only. The similarity of which between the range of vehicles, I found surprising at first. The retractor model, belt stretch & deceleration factors I left up to the manufacturer I used, one of a few that seem to be thriving.
From the amount being sold & installed there must be failures, but I haven't read anything about them. However it's fairly common to read in Old Cars Weekly about someone getting killed crashing their vintage car, sometimes fairly minor (by modern standards) crashes.
The best way I can think of to describe my take on this is...... what if I was in a 60yr old airplane going down, and I had a choice between pulling the cord on a parachute packed by an amateur, or depending on the yoke & instrument panel to save me on impact.
I have no illusion about these being up to current DOT specs, I'm just looking to better the odds in a vintage car crash.
If we end up at a show and you want to take my car for a spin, you are welcome to not buckle in...……..there's no dinger to pester you.