Originally posted by sunshine
Milling is fun. Increases compression by decreasing the size of the combustion chamber or moving your head closer to the piston top. Either way it ups your comp, but too much of it will retard your camtiming negating the milling process and possibly making your car run like ass.
It also moves the valves closer to the pistons, so you have to be careful how much you mill off the head. You don't want the pistons and valves getting too friendly with one another...