383 Broken exhaust stud please help!

Take a rounded tip carbide bit, cut that stud back till it's contoured.
take a center punch and give it a good whack.
Get yourself a really sharp 3/16 drill bit and drill it out.
Take a 1/4 left hand bit and drill slowly it should back it out.
Chances are you may have to pull the head & be prepared to do a helicoil. Not a big deal.