According to my transmission guy it is. I found autotran on a search and emailed them already.
If this doesn't work, I need another cast iron six cylinder 'glide. The shop said they'd use all the parts out of my tranny in another core, no charge. I told them I'd be happy to pay for R&R of the box itself since in the original rebuild all I brought them was my transmission, not the whole car.
I got the impression he is a good man and doesn't want to take anymore money from me. He just wants to make me happy. We'll see.
I just don't have the cash for a modern overdrive swap. Even if I did, this car has been in my family since it was new. My uncle that gave it to me and his uncle that gave it to him pleaded with me to keep it in the family, drive it and keep it original. I am compelled to honor their wishes in return for the gift of such a fine piece of machinery.