you're on the right track..
That bolt should drill fine, it'* not hardened. Center punch what'* left of the bolt in the center of it, start with a small drill bit and work your way up. Use cutting fluid, or any kind of oil, take your time. When you get close to the treads, see if you can get an easy-out to grab it, soak it good with penetrating oil. I like silikroil, 10X better than blaster. If you get that bolt out, you might want to run a tap in the threads to clean them up. If not, nut and bolt time, which could be a PITA, but better than that batter flopping around. Sooner or later, it'* gonna get jostled and short and be a big mess - like with a nice engine fire. Mike
1993 Bonneville SE, frame off resto in progress, will be stock except painted black & chrome t-stars, estimated finish date - spring 2009.
Cars in my "fleet": the bonny project, the bonny parts car, 1999 Olds eighty-eight LS anniversary, 2004 chrys T & C.
Husband, father of two daughters, deer hunter and lover of most things GM, (although I do like my Chrysler minivan) - but nothing comes before my girls..
I'd much rather go home after work and be with my family than do anything else..