Do you have access to air tools?
- air hammer on the thread end of the nut; or,
- pickle fork (ball joint separator) between the nut head and the casing; or,
- try to get a cut-off disk in there; or,
- at worst, pick up a j/yard axle, and just swap everything over. Gives you a chance to detail everything off the car. And, if you've still got drums as stock, you can always do a disk conversion at the same time... (See how it starts? )
Oh! And... how's the rust situation where the axle attaches to the body?