I have done a few. It will take a couple of hours, 2-4 to remove, 2-4 to install, so, have a dedicated 8 hours to do it (who knows, you might only need four of them)
.You do not have to remove the engine, and this can be done in the home garage or driveway with the proper tools.
ie, good floor jack, FOUR Jack stands, some long 3/8 ratchet extensions, 1/2, 9/16. 13mm or 14mm swivel socket and some basic hand tools.
May want to disconnect shift cable from carburetor first.
Raise the car and put it on the four jack stands
probably best to drain the transmission
Remove the torque converter cover, and unbolt the torque converter from the flexplate / flywheel
Unbolt / un attach the shifter linkage.
Remove driveshaft
Remove Six (6) bolts from bell housing to engine. keep in mind , one (or more) of these will hold trans fill tube/dipstick in place and some of the wire loom
Support transmission on a good jack ( I prefer an actual transmission jack, but a floor jack will do, I also like a nice piece of plywood between the jack pad and trans pan.
Remove the transmission crossmember
Check for any other connections to the transmission ( wires, plugs, connectors, vacuum lines etc.)
CAUTION, THE TRANS WILL BE VERY FRONT HEAVY!
With everything disconnected, the transmission should be able to be slid rearward.
Lower jack, and, working carefully, slide jack out from under transmission
I like to pull trans out from under car by the tail housing, , it gives me leverage if I have to tip the bell housing forward and down to clear frame rails and stuff while removing it from the car.
EVERYONE, IF I MISSED ANYTHING, PLEASE CHIME IN!!!
Good Luck!