68 Chevy Shortbed Fleetside

[wwotr]

As I explained in my initial post, my Name is Roger, and I was restoring a 67 Checy C-10 , when I had to sell it 5 years ago due to Finances.
With the Wifes blessing, she has given the me the "OK" to purchase another one!!!

That being said, I've got my eye on one and I think I've been asking all the right questions.
The Truck is a 3 hour drive from me so I've been extensivly asking every question under the sun, to see if its worth my while to drive there.
One thing that sounded "strange" to ME (and mayby not to the seasoned members here, is that he said its got a Big Block from a Pontiac in it.
Now I've heard of 396/427/454, but what type of big block does Pontiac have and what typoe of Automatic Tranny would hook up to that?
350/400/700R4?
He doesnt know what type of Tranny it has, He traded the original owner for it about 2 months ago.
Thoughts/Opinions/Questions???

Roger