The heads of the 5.7 Hemi were milled about 0.020″ for some added compression ratio.
An important thing is the actual finish of the milled heads. Multilayer Headgaskets require a smoother finish than regular composite headgaskets like used on earlier motors. Luckily the headmill was able to pretty much get the machined finish smooth enough. I blocked and wet sanded the milled surface with some 600grit emerypaper and the result was better then I expected.
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