) I borrowed an inductive heater from a friend. I put it on the other bolts and let it heat up until it was pretty hot. The heat transferred to the aluminum pretty well and, as someone previously said, the aluminum expands more than the steel bolt. in the end, removing the broken bolt cost me about $1000 because I had to have a speed shop machinist remove it, so I had them finish installing the rest. 
A small inductive heater that fits around the bolt works well.
