Here is a set of 12 NOS Pistons for the Lincoln v12.  The box is marked 86H D2 and 2.75 +.020. I get 2.766 when measuring them with a caliper.  They all have some light surface rust on the top and a few have some light surface rust on the sides as shown.  The box is pretty rough. These are. Cast steel.  The pictures tell the story.

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