1969 Z28 with 3:31 posi 124379L515933

[Danzo]

https://bringatrailer.com/listing/1969-chevrolet-camaro-z-28-85/#comments-anchor

[camaronut]

I'd swear that the block is cracked -  see pic 110.

[ric1969]

 Looks like it, lots of paint tho ...

[LeonardS]

I think it's probably a casting mark. Or if we want to start a conspiracy theory, he applied some type of metal mender, roughed it up and restamped it 

[GMAD_Van Nuys]

It seems odd that someone would order a 1969 Z28 with a 3.31 axle ratio and a close-ratio M21 transmission:

http://www.camaros.org/forum/index.php?topic=1483.0

[Jonesy]

All those driveline stampings look legit. I agree it looks like a crack, would like to see the paint removed off the pad.

[Delco115]

I may be wrong, but to me it looks as if something was spilled / smeared on the block, painted over without removing it, and that it's not an actual crack. There's also more of something on top of the water pump just below this supposed crack. I also agree that the paint needs to be removed with thinner or other solvent to show the actual block surface.