Good for you! The idea of trying to drill out the remains of a broken stud is terrifying.
Can’t imagine having to Heli-coil stud holes in these blocks!!
Interesting … the exhaust side frost plugs were crap free and the studs that side were easier to remove. The intake side frost plugs were full of crap some almost plugged and studs that side needed more force. You can see in this picture how much the crud help rust out the stud. This could of been one
in danger of snapping.
I believe the water pump flows go through the exhaust side only, whereas water flow on the intake side is less direct.
Probably helps that the exhaust side is hotter too.