Try it if you want, but I wouldn't recommend it. I turned a perfectly good 308 head into scrap iron doing that, and it wasn't because I got carried away with the grinder. There's a water jacket just under the surface there, and it doesn't take much to hit it. I hit it before I even removed enough to get the manifold to sit flat. Some people say they've gotten away with it, but I didn't- and I wouldn't recommend it to anyone else, either.