They all have cracks...literally. Every stock turbo head I own has at least one...most have multiple cracks. They don't leak into the coolant or oil though so it doesn't effect how it runs. Like 95% of all turbo heads being run today are cracked...
Where does one look for cracks in a head? I had to pull a head off of my 140K motor today, checked out the chambers, and didn't see any cracks. did turn up this though