The stock steel gaskets are like .019-.021 thick, the 8553 crushed are about .046-.05 depending on the batch and who measures, mine were. 046... so at say... .045 milled.. -.021... It's the equivalent of having a potential .002-005 thick head gasket ..yielding about 3.5cc or so less than stock chamber volume ....you've only dropped the head down around .022 ...no need to mill the intake side.
