Measuring how much a head was shaved?

One if the shops I deal with will roll those Chevy heads and angle mill them but not so much as to make it visible to the track inspectors.

They did my sons modified motor and I told em to shave 'em all he could. When we put the engine in one of the guys helping us asked if we had a 12-1 motor...rule sez 9-1.

Ran like 14-1.