I've decided to re-assemble this and run it, see what it'll survive. First, a pic of the location of the pin-hole crack, which I put white-out on:

 

And here's a pic of how I found the crack:

 

Consider it extra oiling for the cam

Kind of a strange place for a crack

 

This is what happens with blind holes when you tighten the bolt, not realizing there's oil or water already in there. The results are usually far worse than this, especially with aluminum blocks. I've seen an aluminum LS1 block split wide open. That was from the second-to-rear, outer row head bolt on the driver side.
Still, I'm gonna clean it, machine it, re-clean it, JBWeld it, and then assemble it.
My testing procedure requires good hearing, this one didn't sound much different from the others. I wasn't sure, so I took a break, then came back to it. I had my pressure regulator set to exactly 100 psi. Be sure to do your listening when your compressor isn't running.