Torch always works nice, if not then if you have air tools (air hammer) chisel them bast*rds off. It seems to work better chiseling when you can drill a little of the head off. Chisel the head then hammer the stud part out. Takes some time but it can be done. They are S.O.B.'s All I can say is HAVE FUN!:beer
Easiest/fastest way I've found is to "cross" grind the heads, make an X across them with a thin cut-off wheel all the way through. Then air-hammer, once they have the relief cuts the bulk of the head will crack off when hammered.
Any path you take sux.