273 time to 'fish or cut bait'...

Higher compression is the way to go IMHO, for what the OP wants to to: stop-light to stop-light demolishing of the competition and then highway cruising without too much fuss. I was thinking of head shaving but did not want to complicate his life.

What head gasket did you use? That might be good info for the OP.
Dang, I knew someone would ask.