69 transmission ?????

[c3006]

I am resurrecting my uncles old 69 c10 that been sitting in a barn for 15 years and am like so many hopping to find help and guidance on here. The truck started like as a big block automatic but had a 307 with a 350 turbo installed and then when that motor expired it was relegated to the barn. I have built a 327 and have a 400 turbo with a short shaft being built now and was wondering if this combo would go back in place of the one I'm about to pull out or will further mods be necessary. Thx for any help or advice offered. Clint