i used two different impact guns, one being a Snap-On that is krazy strong. it's what i use to remove seized main cap and head bolts with at the shop. i also attempted to use a 3/4" breaker bar with a 6 foot 2" piece of steel conduit over the top and that also did nothing. ask chevellefirebird (Nick) he was there. it started to destroy the head of the bolt but then the Snap-On socket i used stripped. each time i tried to turn it i sprayed PB Blaster on it for about 2-3 seconds.

i also tried hitting it (with the nut on) with a 5lbs sledge and even a 15lbs sledge to "shock" it free.

the only thing i have not done is to use a torch to heat it or even just cut it off and i'm not doing that.

and yes it was an impact socket.