Looking at the original posters comments about 'DZ', wasn't it a practice to hand write the motor prefix on the visible side of a head to make it easier for the person who had to retrieve the block from the rack? I'm sure we have all seen the pictures with motors and writing on the blocks and valve covers sitting on the train terminal loading docks. As I understood it, on racks of motors, there could be different prefix codes and unless one climbed onto the rack to look at the pad stamp the grease mark on the head made it easier to distinguish. I understand that marks on a bare block being assembled have had them painted over. I agree that some cars are way overdone with marks. I've seen a Chevelle at a show recently and it looked like someone shot at the engine compartment with a paintball gun.
When you step back and look at the PBT, linkage paint dabs, the occasional surviving factory post-assembled inspection dabs (have them on my steering joint to shaft bolt), surviving marks on firewalls (I'm not referring to those under the blackout), marks written inside front end panels like extensions and valence, and the white 'X' on the washer fluid tops, there is already a lot of 'graffiti' when it left the factory.
Mike
