I have a 4.3 Merc (1993), I was taking the 1/2 plugs out of the exhaust manifold, one came out very easy the other is not so easy. I didnt want to crank to hard because I was afraid I might crack the manifold. I drilled through the plug so that the sides are very thin, thinking I could pry the sides out, but it still is locked in there. I need some ideas on how to get it out or if somebody has a trick for this. I can heat it up, but im not sure on how hot you can get the manifolds before you damage them.
