77 R model enging block stamping numbers??

[Lmackattack]

I'm getting ready to pull my air compressor off and notice these numbers stamped into the passenger side of the block to the rear of the air compressor.

What are these numbers telling me?

[Freightrain]

Good question.  Been curious myself.

 

[Lmackattack]

Its hand punched so I figure it has to be something from the factory and now that I see yours has it as well that would make sence. Just never noticed it before

 

[Vladislav]

Those numbers are always there. I have 3 or 4 E6V4 blocks with them and about the same count of E6V2 either. They're not an engine serial number definitely. Probably some internal factory markings. Might matter a group of parts you use working with a parts list for identification but I'm not familiar with that subject.

One of my trucks has those put into the registry papers as the engine number. Looks logish if you don't know of how that number should be marked. And that's a kind of issue for me now since we're able to swap an engine legally if install a similar one. Which means similar model designation. In my case I couldn't use another similar E6 block in place of the old one since that different one is stamped differently in THAT spot.