Do you mean an engine MOUNTING bolt?? Air s work fantastic...... Sometimes I grind or Dremel the bolt head off, snap the nut off and then deal with it.
If the motor is being rebuilt, it is MUCH easier to get it out after you grind that crap off. You drill it on a mill or press it out, etc etc etc - piece of cake.......
Even engine cases, I grind the head off, remove the case and that exposes a shaft I can grab and use MAPP gas on the aluminum. Oxy/acetylene scares me as I don't want to melt the aluminum, I don't have that pressure and mix down yet and staying under 1000 degrees can be difficult.
All our government does is distract us while they steal from us, misspend our tax $ and ruin our country