1966/67 barracuda bucket seat interchangeability
In conversations with Legendary the 66/67 seat frames are the same for both A and B Bodies - tracks and seat covers different. I know the 68/69 A Body frames are the same and different from the 66/67 frames (unknown if they’re the same as a B Body). So I would say the hardbacks from the 66/67 are not going to be easily adapted to the 68/69 frames.
I’d say the 66 seats with the 66 tracks should be easily adapted to the 67 floor pan with spacers or whatever else is needed to make them fit. I am putting 66 seats in my 65 Dart and there’s enough difference between the 65 and 66 tracks I needed to add 1 spacer and drill new mounting holes. No comment on the 69 track swap to the 66 seats. Personally, i’d Use whatever seats that float your boat and adapt the tracks to fit.