Replacement Seat Foam

[Bozman]

I've finished painting my 1971 Avanti and have replaced the carpets, now I'd like to address the passinger seat foam, the previous owner must have had the driver seat and rear seat foam replaced, they are in great shape and comfortable,  but for unknown reasons, the passinger seat was not done. It's foam is flat and crumbly. The vinyl on all of the seats is in great shape.  I'd like to try to tackle this problem if I can.  I know there are preformed foam seat bottoms and backs on the market,  I'm wondering If the seat foam used to make my seats is for a standard GM, Ford or Mopar seat, that I can order.  I'm going to try to post a couple of pictures of the left and right seats in hopes that someone will recognize the seat, and can stear me in the right direction.  If all else fails I'll try to find an upholstery shop.