4x4 sm420 to sm465 208 case

[67ranchhand]

Hello everyone, I have a 67 k10 with the sm420 and Rockwell case. I am going to drive this truck as much as I can. Maybe a daily driver. For reliability purposes and since the parts are hard to find for this trans and case, I was thinking about swapping it out with a 265/208 case. I have this trans in a square body with a cracked head 6.2 diesel. I would rather have the 205 but this is what I have. Has anyone done this swap? Is this a bolt in or are there modifications that need made? Driveshaft length? Mounting? Thanks guys!