Do what us converted Corvette owners do. Get the biggest pair of vise grips you have and clamp on as tight as you can. Now get your most serious framing hammer and whack those vise grips (don't forget righty tighty, lefty loosey or it will turn out to be a long day). If that thing doesn't break free, somone welded it so buy one of those kits where you can extract the oil throught the dipstick.