Thanks for the input so far, everyone, but I think this post is getting off track. There are several benefits to proper quench/squish other than simply making more horsepower. Obviously, not everyone agrees with these benefits, or on the amount of piston-to-head clearance that's required to attain them. I'm not trying to be a wise guy, but it wasn't my intent to debate this or to defend my position on quench. I do have some timing issues in my engine, and I am working on addressing those separately. My objective in this post was to get opinions on whether or not .040 clearance from piston to head is too close in my application. I respectfully ask that we try to stay on that subject.