[At-Least-It's-An-Evo]

Your only good options are to increase the combustion chamber volume or get different pistons. You would have been fine with that dish cc on a 2.0l motor. A really thick headgasket wouldn't be good for squish, which would make the car more likely to knock than a car with the same overall compression ratio, but with the correct pistons. The Cometic and Mitsu metal headgaskets that most of us run are already a bit on the thick side. I don't know how metal you can remove from the combustion chambers without ruining the quench areas.