Don't drill too far, you'll enter the water jacket.

Buy/rent/borrow a Right angle drill and shorten the drill bit.  (or
Right angle chuck adaptor for your existing drill).  Use a 110v
drill, cordless drills won't be good for drilling out studs.

Better yet, get a reverse drill bit and run the drill in reverse.
If you're really lucky it will spin out the stud as you drill into it.

>I guess the things to not do are:
>1) drill into the engine block...stay straight into the bolt
>2) break off the easy out (as it's hard to get/drill out)