I left mine at the machine shop, they normally crack in-between the 2 valves on the end chambers, i'm sure mine were toast, the crack went down on each side about 3/4", also found cracks on the other head, so i junked them. On the 1 chamber that was really bad, showed signs of pitting on the valve & seat, so i'm sure coolant was getting in.
Most machine shops i've called are very familiar with the cracking issues on these heads & don't want to mess with them IF there cracked, your just rolling the dice whether they will leak or not, thats if the machinest doesn't want to jack with them & you just throw them on "AS IS".