I know if you resurface a head from a 616/617 you need to use thicker prechamber washers to raise the intrusion of the prechamber into the combustion chamber. It could be the same for the 603 heads but I won't swear to it.
Maybe someone else can chime in.

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DJ


84 300D Turbodiesel 190K with 4 speed manual sold in 03/2012