I looked at a vintage Hemi block today, did Chrysler make a special block for NASCAR? and how would you identify it?

The guy did have those cool HEMI NASCAR valve covers that are clearanced for the exhaust valves/rockers on his shelf.

What's the casting date? I know Chrysler sold a 'fuel' version of the Hemi block through Mopar Performance back in the mid '70's. I have one with a '74 casting date.

If it was cast early enough, it would be a Hemi block destined for NASCAR; after that it might be sent to a NASCAR or a drag racer. After that, say mid-'65, it could have been destined for NASCAR, drag racing, or Street Hemi production.
The earliest blocks (late '63 to very early '64) had strength problems that were solved very close to the Daytona race.
I'm pretty sure all Hemi blocks were created equal once the early issues were resolved, but if there's a way to authenticate some race-shop engine-builder's stampings or modifications, that would make it a cooler piece than the one in my car...

They might of, they certainly did a lot of special parts for those cars back then.

I had a guy show me a 426 wedge block that had a Hemi bottom end (cross bolted main caps). He said that was what the NASCAR guys ran back in the early days. It was a real block, I looked it over fairly closely but I didn't have a camera with me. I don't recall the casting numbers or anything which is too bad.