You can grab tracks out of almost any 70's passenger car. Even those with bench seats, of course you'll need to find two different cars with bench seats to give you the 4 tracks you'll need.
For example, the seat tracks I used here (see attached pic) were from some 70's Lincoln with a bench seat that I found at the wrecker. I didn't use factory bucket seats but these tracks would have bolted right up to those.
The whole article is here:
http://www.fordmuscle.com/archives/2...rior/index.php
Good luck.