They won't fit any car except mine, so you might as well let ME have them:devil::devil:
I'm not certain about 71 tracks, but I do know all of the frames were the same size from 66 to 71/72, just the release button locations and back/side material were different (metal/plastic).
If those tracks don't fit, you can always modify them to fit. You won't be "original" with the 66 seats because they have metal backs and sides, and no release button. THe 71 is supposed to have plastic backs and sides with a release button in the middle of the seatback.
Beautiful seats. I'd love those in my car. New everything by the looks of it. I don't imagine those were bought off the rack? Interesting they have detents on both sides of the seat. I can see a release rod going to the other side in that one pic. My seats just lock on the one side ('66).