Machining M70 head surface ?

[BMSman]

My inexperience got the better of me today... whilst removing one of my cylinder heads I must have bumped a locating dowel (which are quite sharp) and nicked the head surface.

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2nd time around I realized the technique is to rock the head from the lower edge and then lift it clean away.

I'm assuming I'll need to get this skimmed and was wondering how much it is safe to take off? Pistons look to get very close to the head. Dings are not very deep, guessing about 5 thousandths will remove them.

Head gaskets remained fully intact and left very little residue on either surface to clean up which is good. Lots of corroded bolts but the head bolts were clean and came out easily.

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[cartoonz]

You're going to want to clean up those heads anyway and probably do a valve job. The machinists can make those marks disappear easily, no worries at all. You could even do it with a stone, but it makes more sense to strip them down and have them checked for warpage while you have them out.