[57taskforce]

I would try using a 3/8 battery impact on the Lowest setting forward and back, if it doesn’t budge move it up a power setting. I’ve found you are more likely to strip the head on them by hand if they are really stuck than with an impact and light power. Smacking it with a hammer and extension as said above is a really good place to start.

I easily drill about 10-15 of these same plugs a month on the engines I build at work. It’s not hard as long as you can get a drill in there. Drill it out as large as you can without catching the threads in the block. Then use the biggest easy out you can get into the hole you drilled and gently but firmly drive it in tight before you start trying to loosen it. Normally the heat from drilling it will work to your advantage. Don’t use a small easy out what ever you do, you will regret that when it snaps off.