If you had a lift, air tools, and a transmission jack, and you didn’t give a **** about breaking anything, you could have it pulled in 40 mins.
Otherwise I’d figure a few hours to get it out and a few more to get the new one in and brakes bled/adjusted.
It took me two nights probably 7 hours total to swap complete rear assemblies from my 65 to my 67. That’s on the floor, jack stands and hand tools. I have done this many times, and both cars are low mile/low rust cars.