If you are not looking for original seat there are many that work.
I used 88 Lincoln Towncar front seat( fixed as mine is a 4DR. I measured across the opening less 2"s and looked at different cars until my buddy gave me the Lincoln to strip and the split seats fit. I took the leather off the rear and had a fellow put them on my wagon seat.
My buddy used 2000 Pontiac? leather front seats and rear also, no mods to fit in.
I have some 57 bits and pieces I am not going to use so If you need something I may have it. No big pieces.