ProComp/Speedmaster aluminum heads

plain and simple, squish speeds up the charge and spreads it even across the open chamber, for a more even explosion
Squish physically mixes the flame with the mixture making the burn more rapidly, thus reducing detonation
minimum effective quench is .035
Air/fuel is swirled into a finer mist creating a faster burn, which in turn minimizes the ability of hot spots to form in the chamber.
With the fuel particles being condensed more finely , the mixture is easier to light.