I have seen the WBX broken stud problem once or twice 
the studs become corroded etched mostly at the base of the stud near the block and you might see that more than stud that is pitted when you look closely. the stud is often not willing to turn even with a nut or extension of some sorts added to it. I have had limited luck drilling this as they are hardened and down in the corner of the coolant jacket. I have sent them to Jerry's Broken drill and tap Santa Anna don't have the # . they have metal disintegrator that cores the stud then it comes right out. to do this the block must be stripped and cleaned
or you could by a long block from me 
Bob
http://www.bostonengine.com