PB Blaster is the only stuff I'll use now. I let it soak overnight (currently doing for a timing belt, H2O, clutch etc). Try some heat on the bolts also. When I did my kids 88, the mechanic before me broke the welded nut free also-he/she must have been crankin on it.

I haven't had these bolts off for 3 years, so we'll see in a few minutes. I have no air tools either. Crank nut is always fun!

 

Also how are you guys getting to the crank bolt? It doesn't seem like there is enough space to get to it from the top of the engine bay. I can see doing it from underneath the car, but with a seized bolt, I would imagine it's hard to do it on your back. And to do it from the side you would need one hell of an extension.