Burly
Sort of the same problem on a smaller scale, on my 32 Distributor housing and removing the old oiler to replace it. Tried "gently" with a pair of Vice Grips which "morphed" in to a "hammer fisted" 4000psi tightening of the vice grip on the old oiler and still didn't seem like it wanted to move. SO, I turned it on its side and put Ballistol around the base of the old oiler and let it sit for 24 hours THEN was in the shop the next day SO another run of Ballsitol around the base of the oiler and another 24 hours later.....POOF, a gentle grip and nudge and it came loose and I was able to pull the oiler out with NO Issue
YOU will find that Ballisol is amazing stuff.....A must have in my shop AND in my loading/cleaning/Gun room!!!