Okay I thought you were putting 73/74 E body seats in a 73/74 E body that had the wrong year seats.

You are putting E body seats in an A Body. I see the more clearly.

It will be easy to modify the seats to be left or right.

The tracks may be a different story.

I believe the difference in the seat tracks has more to do with mating the floor pan to the seat style.

Do you have A body seat tracks?

I have some Ebody Seat tracks in the basement and I can measure the mounting points tomorrow if that will help.