[Jonesy]

From John Hinckley:

Yes, the pad was masked with tape prior to the engine entering the paint booth (along with masking all the other items Engineering specified). Once the engine left the paint booth, the only way to identify it was by the suffix on the pad stamp so they knew which conveyor spur it needed to be routed on so it went to the correct spot on the rail shipping dock so it went to the correct assembly plant. Those engines were moving at 300 per hour (one every 12 seconds), and they had to be able to read the pad stamp suffix quickly. The suffix code scrawled upside-down on both sides of the block in grease crayon in the first bore air-gage station on the engine assembly line (which told everyone on the line what innards to install in that block) was covered by the paint and couldn't be seen any more