A hand held blow torch using propane is a good source of heat. When you try to remove the bolt, use plenty of penetrating oil. Liquid Wrench is a good choice, or any other type you like. Then work the bolt a little at a time. Counter-clockwise and then clockwise in very small increments. As it starts to turn, go a little further each time but turn it both ways as you go. You should be able to tell if it will turn out after a while. Turn it slowly counter-clockwise if it feel like it is turning out.
Even if you break it off, there are ways to remove it. In other words, it isn't a world-coming-to an-end issue... You never know until you try. And the cost to try is ZERO! The plus's are you will both remove the bolt AND learn how to do it as well. JMHO
