Mystery Markings

Gentlemans,

This spring, in the name of citizen science,  I've taken to trying different methods of cleaning spare parts that I've accumulated. These experiments have revealed some odd numerical stampings on a spare block, head and cam that I never noticed before (given that they were covered in crud before.)

Admittedly I have not torn down many motors in my lifetime. But I am genuinely curious and my searches haven't revealed much.

My best guesses are that the block was marked by a machine shop who had shaved off a .003", and perhaps, in an effort not to mix up customers components, stamped the cam and tower with the same numbers so that the re-assembler had a fighting chance?...they seemed too sloppy to be cam grinds...

P79 head (unknown year), F54 block (also unknown year)

BP