I've done a couple - the first one took a weekend in 1982, working with a few friends in a well-equipped shop. We pulled a 327/TH350 out of a body-damaged '69 BelAir I'd bought for parts, pulled the very tired 307/Powerglide out of my '68 Impala, and dropped the 327 & tranny into the Impala. There were a few glitches, like modifying wiring harness, but overall it went OK.
The other one was in '88 - I worked on my own over a couple of weeks of evenings and weekends to pull the engine out of a written-off '80 Mazda GLC and drop it into my '79 GLC Sport. It went very well, but was time-consuming because I had to build wooden dollies with castors and so on.
Part I - I drove the donor car into the garage, pulled the engine using a chain hoist hung from a rafter, pushed the car out into the back lane and then up beside the garage, dropped the engine onto a wooden dolly, and pushed the engine & dolly off to the side.
Part II - Drove the recipient car into the garage, and pulled its engine. Then pushed the car out into the back lane, dropped the old engine onto a 2nd dolly, moved it out of the way, pushed the new engine back over, and lifted it.
Part III - Pushed the engineless recipient car back into the garage, and dropped the new engine it. Switched over a few parts - distributor for sure, as it had points, vs. the incompatible distributor from the new engine which had electronic ignition.