White Feather

I have a block that it appears someone may have hydrolocked a head bolt in and cracked at least one of the head bolt holes...

The very far rear passenger side head bolt hole I noticed was leaking when I "charged" it with compressed air, I assumed at first this was due to the bellhousing bolt breaking into it but I shot some wd-40 in there and viola, it is leaking just a tad at the radius next to the rear cover where the blind bolt boss is in the casting...

I went over all the other bolt holes with one of the rubber tipped air nozzles and would charge it then hold the nozzle so it couldn't leak down and none of the other holes seem to be leaking any air so far as I could tell.

I don't know any other way to check this, anybody have any ideas?

Should I just scrap the block on the offhand chance that one of the others is cracked, or is it worth running it to see what happens?