Block ident and missing numbers

[jeff74]

Are there always numbers on the block in front of the passenger side head? I can't see any evidence of any

I finished the engine disassembly this afternoon, the pistons don't have any oversize marks, I need some better tools to check for sure if it's been bored , but with a caliper it's pretty much 4.000". Wondering if the block has been ground.

3970010 block , K 7 date code? I thought it was supposed to be more digits. It's a four bolt main block.

It's been somewhat apart before .. lots of timing gear plastic teeth left in the pan..