I suggest NOT cutting off the bolt head, only as a last resort. But before you put on the socket of choice, heat the bolt with acetylene, or what have you, then squelch it with PB Blaster or similar. Do this several times over the course of a few days. You need every advantage you can get in removing the bolt. An even better way is a mixture of acetone and ATF. Soak the bolt and let it weep down into the threads.
