Porting small block 915 j-heads

Got a little too greedy I guess.

I wonder if it was just an odd void in the casting.
Seems like the whole area around the hole is paper thin.

Maybe the head had some core shift and they also got after it a bit too much.

I ported some BB stage V heads once, there was a void in the casting in an area that specifically showed in the instructions they had added material there for porting.
As soon as I touched it with the burr it blew a hole right into the water jacket.
Sometimes **** happens.