273 to 440 swap
I'm not a big guy, although I'm bigger than I was thirty years ago (I've been 5'10" since 1975, but have gone from 125lbs in 1978 to 192 a couple of years ago and back to 172 now) and I've never had trouble bringing a big block a-body down from speed in a panic stop with manual disc brakes. The only power disc brake a-body I've owned was my old 67 fastback which I swapped to manual brakes. The effort just isn't that hard.
Power steering is another story. I've had shoulder issues since my 20's, but I have built several manual steering cars as well as power steering cars. At my age and the way I like to use my cars I'll go with power now.