ORIGINAL: Frost_
ORIGINAL: ericheller
you need head shims because the higher nitro content increases compression...
Actually it lowers the point of volatility, the compression ratio cannot be changed except by changing the volume of the combustion area.
well by shaving the bottom of the head off lets say .05 in. so that it sits lower, it will decrease the combustion chamber, and slightly increase compression. it is the same concept as taking out a head shim except there is no head shim.