4L80E conversion

[GR8-68]

So I have been doing a lot of research on converting my th400 over to a 4 spd auto. So a fellow worker today told me he had a 4L80E with 40,000 original miles on it he would sell me for 300. To me it sounded like a decent deal but not really up on the pricing range on these.
Also what is involved in getting it to work behind a sbc 350? I have read the easiest and cheapest way to go is the 91 -93 6.2 6.5 diesel trans computer. There is just to many opinions on the internet to seem to get a solid true answer.