<VV> Exhaust Manifold Studs to Exhaust Pipe.

[Allen Miles]

I am planning on installing dual Exhaust from Clark's .  I examined my exhaust pipe to manifold studs and found them badly eroded . Soaked them with WD40 .  I am almost positive at least 2 of the studs are going to break when removing  Exhaust pipe .  Is their a way to drill out the studs with the Manifold on the car and retap the threads to install anew stud.  
Thanks  Allen