My experience years ago is very similar to all of the above! I broke a socket with a breaker bar and a 4' pipe and two "Lard @$$es jumping on it to have to give up and use the torch, and that was every bit as tough as mentioned by everybody here so far! So be Careful this may take some significant torque to move, which is real dangerous on a jack even with stands. I would use the biggest impact gun you can beg borrow or buy with a big torch. I have had pretty good success with the heat and quench method lately, heat both ends with the biggest tip on that torch until "Red" and let it "heat soak" to the inside and then let it cool and spray when warm (400* this is the point that spit will still dance in a ball on the steel) try and use a low flammable spray or just deal with the flames (water) and repeat a few times. What you are trying to accomplish is to have the bolt expand from the heat and break up the rust , and then "draw" the lube in as it cools, not the fastest method but effective. You have to use a lot of heat as you don't want to heat up everything, just the bolt so a small flame from a brazing tip or even a turbo propane torch will not work! They will let everything get hot together as time will let the heat transfer to the bushing and the rubber* (*which you would prefer stay intact to hold onto the bushing so you can hopefully spin the bolt in to free it up so you can remove it without busting up the frame mounts). I hope my explanation is clear to you, my "High Speed Typing" allows me to forget what I am trying to say and sometimes I leave parts out
Harry P.S. WD-40 really burns too well for this method even if you are patient enough to wait for the 400*ish temp! but this what I have so I deal with it, Dick's wonder Oil sounds pretty promising
I wish I could find it over here in Canada and I forget when I'm in the US I want to try it out.
I'm not a hoarder I'm a preservationist 78 Monza Spyder (~Soon(ish +/- I guess) To Be 2+2 with Spoilers)