I don't know exactly what would be involved to convert to auto
but I know you would need more then just a auto transmission to pull it off.
I wish I knew of a reputable rebuilder myself
as I have my old 5 speed that I want to rebuild and put on the shelf
I got lucky and found a lo mile used piece to replace it
I would keep looking for something like that
I never found a rebuild kit but I really didn't look hard for it either