Your best bet is to measure the stock width and go from there, a visit to the local junkyard will almost certainly produce something (if you're looking for bench seats). Bucket seats can pretty much be made to fit anything. My '41 sedan still has the stock seats and I'm happy with them but "to each his own"
This is what tape measures are for. In any case, cara of the 40's taper towards the windshield so if you do find a later bench seat, you need to measure the seat at the front, not the rear to take this into account or else you may run into the door panels. No rear seat will be a direct interchange. You are going to need to modify something. Sent from my SM-T350 using The H.A.M.B. mobile app
i have a bench seat that came with the car......but it weighs a ton......i can bearly move by myself......i have no back seat.....thats way i was looking for a doner ......
For a back seat take tape measure to find one that in width and height. I think width is more important Than height, you move it up and down for a better fit. 97 Grand Prix seats in my 39 pontiac