David, you CAN drill them out just make sure you have a good drill bit. Drill small hole, then a bigger one. Once you get close to the right size then punch them out.
OR...take it to a WELDING shop. Let them heat the stud area up red hot and you will be surprised how much easier they will be to come out.
I feel you pain though as I am having to drill some broken studs out of a 283 exhaust headers.
