I didn't ask for the head to be milled but when I picked up the guy that I talked to told me they milled it slightly (he said either four thousandths or forty thousandths) I wasn't really paying attention as I was looking it over. But then again one day I was told a retainer was flawed and I had to get another one from skunk2 and the next I was told my head was ready, so I went to pick it up and the guy looked at me like I was stupid and asked if I had another retainer, so who knows if the head was even milled in the first place. I just looked over the receipt and if they did mill it they didn't charge me for it. I really don't like playing with the cam gears because one I really dont know what I'm doing when it comes to that and two I know the if I adjust one too far motors aren't too forgiving.