Will,
I had Fiero seats in my '74. The seat bottom has a very deep foam pad. I cut the part off that hangs down between the tracks. I used a hacksaw blade and just sliced off the part that hung down. I think it removed about 2" of foam, or about half of it. I used Recaro seat tracks because they were lower than stock. I'm 5'10" and I had no height issues with the stock floor pans. They were also very comfortable, and the speakers in the headrest were a bonus! These seats also allowed my back to be deeper into the car (closer to the firewall).
Michael