wardell, I don't know of anyone who makes a bracket or kit for that. If I were you I'd go to the pick a part palce nearest you and find two good seat motors from a newer vehicle and make them work. Make a bracket to mount it to the seat you have now, that way if those ever go bad just go get a new motor for what evver type of car you got it out of. Its a better option than getting a seat motor from a rod company that they only sell.
mid seventy-eighties GM seat tracks are very adaptable, but you are on your own just get a set that look close, don't worry about width its the length and height that need to be closest to what you have make it strong.
Like they said, get out the tape measure. Odds are you will be able to find something close. I would replace the whole seat though. Could be alot simpler that way.
If you go with a set of seat brackets, you might have to fabricate some adapters. Might be easier for you, but for me it would be harder so I would just have to replace the seats. Either way might involve some work. But that is the fun part I suppose.