I sat in a guys truck at a show last summer. It was a '49 with an older Dodge Dakota seat. Sat pretty nice. Take some measurements and stroll around a wrecking yard some weekend.
There's some interesting comments on this board (just a few topics down from yours) titled "Neat seat modification for AD's", you might find something that works for you. Good luck!
By the way, I see this is your first post - WELCOME to the Stovetolt Page!