Seat tracks used to be hard to find, but I think they are a bit easier to come by now if that's the problem. There are springs in the bottom of the seat that go bad. Taking a seat apart for a rebuild is pretty easy, replacement seat covers and new foam and springs will turn them back into something that's as good as the 1970's. Entire seats are also out there but shipping can be a bit of a pain and they most likely need a redo. The new seat covers are an advanced do it yourself project, but all in all not that bad of a job and you will need to buy a pair of hog ring plyers for about $20. It will be a bit cheaper to rehab what you have over buying new seats. Procar has a couple of different seat types and are about the most economical out there, I think they have tracks but im not sure they are listed for these cars. So some fabrication may be involved in getting them to fit. Another advantage of the Procar is if they recline, and some have side bolsters for a tighter fit. If youre adventurous there have been some guys that have sourced late model seats with power, I think one guy used some from a newer gto, and another out of Z car. But there is more fab work to make these go in.