How to tell how much heads have been milled?

[SinistrV6]

I'm having to replace one Champion Iron head. How do I determine how much has been removed from my one good head?I'll need to mill the new one so compression will be equal.

 

[UNGN]

Sometimes the machine shops stamps the head in a corner with a number like "006" indicating they skimmed .006" off. At least the goog ones do.

I wouldn't sweat the differences, too much. You can use a piece of glass and a syringe to "CC" the combustion chambers, if you are really anal. I would think the blending champion does on the combustion has more effect than the milling.

 

[SinistrV6]

Doesn't matter?

UNGN,
I'm pretty sure that Champion milled them once and I know that I have. Assuming .006 each time (that's what was done last time) you don't think that .012 closer to the pistons will significantly alter compression ratio? If not, that's just one less thing to worry about! Are forced induction motors affected less by these differences than NA motors?

Thanks,

 

[UNGN]

Champion also cleans up the combusion chamber and unshrouds the intake valves. This more than makes up for milling .006 or even .012 off the surface.