If you're going that far, it may be worth your time just to source a rebuilt head or farm yours out for a rebuild. Have it checked for warpage and cracks, valves and seats ground, check the wear in the valve guides, valve guide seals, etc. Be aware that you're talking about a head gasket job in the works as well. If you're paying someone to do the work for you, expect a fairly hefty bill (north of $1000). The cost to refurb the head will depend on what is worn and what needs to be done to it. If the valves are worn and you need new ones for example, it's going to cost several hundred more than if your existing ones can be reused.

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Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)