What does it mean to mill the heads .15??

 

Its how much the machine shop is taking off the bottom of the head, the side that mates with the top of the cylinder block. It is done to increase your compression ration, BUT, you must beware if using an aftermarket cam that the lift is not too much as to make the valves hit the tops of the pistons because milling brings the valves closer to the tops of the pistons.

 

I don't think you can mill heads .15... Do you mean .015?

 

yes i do mean .015