3 on the Tree Swap to Automatic

[KJ69]

Hey everyone! I am new member and I currently have a 1969 C10 Shortbed pickup "Project" with a 350 small block and the original 3 speed on the column. I already have a 400 turbo transmission and I recently purchased a 1971 automatic steering column to use. I am also considering getting rid of the 2 piece driveshaft at the same time. My question is what else do I need to get ready for the swap? I have heard I need a new crossmember and linkage, but I need more details and photo's if anyone has any.

Thanks for any feedback you can give me!!