
Installing 3 point belts in my 72 F250
I noticed my 72 F250 had rubber hole covers in the side pillars, so I assumed there would be a threaded hole behind it for a factory option not fitt to the truck off the line. Unfortunately, no threads here, just smooth holes.
I want to upgrade to 3 point seatbelts, already have 2 from LMC in my possession. Am I missing something obvious here?