Sanity check re engine swap options/planning

Really appreciate everyone's input, it's giving me a lot of great insight. I'm out of the country for two weeks shortly so any action will have to wait for a bit but that also gives me time to do more brain work. Obviously I don't want to just jump on the first shiny thing that comes into view and regret it later (even though a 1973 440 and matching tranny just popped up on Craigslist, though I know by that point performance had dropped, at least as it came out of the factory). I also want to make sure I'm doing the brakes justice as well of course.