Duh, I forgot, you are 2 cylinders longer than normal!

Do you have access to a lift or some wheel ramps to get the front of the car high enough to use a long breaker bar? There should be enough compression to allow you to yank the breaker bar sharply and quickly to break the bolt free. Might take a couple attempts, but should be feasible. Tightening will be a bit more difficult, but should not be impossible.