Originally Posted by
ala_xfire
1. weld on a nut and turn it out
2. drill and ez-out ( probably won't work )
3. drill CENTERED out to the threads and re-tap
Option #2 is good, use a reasonably large EZout, apply penetrating oil and/or some heat, not too much heat.
Option #3 is tricky to do as you have to be on the centre line all the way through.