Re: Advice on removing snapped s/s bolts from alu block
You have lots of suggestions - which ones might work really depends on the exact circumstances. If you try to drill it out invest in some left handed drill bits.
There is another alternative that save my as* a few times, including the time I snapped off an extractor, inside a hardened stud, inside a magnesium casting. It's called spark-erosion and works just as the name suggests.
It's not cheap and there aren't many places that do it (I only knew of one in the LA area when I lived there) but if you can find one locally, it's the best way to go for difficult extractions.
If you can't find anyone, ask around old fashioned motorcycle shops, classic car/motorcycle restorers, machine shops that rebuild engines (especially exotic engines), etc.