I am coming down the home stretch on a 440 swap out. I have a 79 sweptline, macho. It had a 360 in it. The items you ask about (what changes on the swap out) is hard to say for sure, because many of the parts in even original late 70s tucks are from the parts bin and some are not even Dodge/chrysler parts. Steering box is one of them, although you wouldn't necessarily need to swap that out with the bigger engine. My big ones were: the bell housing on the transmission - the small blocks won't line up with the big blocks. In my case we took out the trans, rebuilt it in a casing that fits the 440 big block. You will need a new torque converter. The brake booster won't fit as scheduled, but there are a couple places out there to get smaller diameter brake booster. I got a pretty gold plated one for $100, looks cool. Unload the radiator, the 440 will like an aluminum one and an electric fan. Of course you will need bigger and custom built/fit oil pan. Other than that, my swap out wasn't so bad. Just takes forever finding parts, so half of the parts I got I had custom made due to covid, people requiring cores before they will ship a part, or just not wanting to rebuild some POS part so I found folks to make custom ones.