So after some searching I learned pre-89 third gens do not have shoulder belts in the rear. 89 and later can be a direct bolt-on for a 4th gen belt.

I drive and 86 and have the 4th gen parts but am looking for instructions and parts needed to get them to safely fit in my car so the kids can ride in the back once again (they used to when they were in 5-point harnesses).

Can anyone point me in the right direction? Is there a thread or tech article I missed?

 

I would assume you could get the mounts for the rear shoulder belts out of a 89-92 car, then weld them into your car in the same location. Then of course, get the appropriate plastics for them as well.

 

I did this conversion on my 84 T/A this past spring. It was a pain in the butt. I cut the section around the mounting brackets out of a junk car and drilled out the spot welds to separate the bracket from the wheel well sheetmetal. The passenger side bracket sat nicely in place, but the drivers side wheel well is shaped a little bit differently on the earlier cars than the later cars. I had to make a 1" diameter indent for clearance. Also, the 4th gen retractors are a bit taller than the 3rd gen ones. That meant I had to heavily modify the drivers side bracket to lower it enough for the plastic pieces to fit properly. If you can, I suggest getting 3rd gen retractors to use. I think it'll make it a good bit easier.

 

I did the same conversion, but used 3rd gen retractors... same problem. Upon test-fitting the plastic, the retractor sat way too high. The only way to get the plastic to fit was to modify the wheelwell to let the bracket sit lower.