Since the stud is evidently a bolt, of which the head has been welded to the body, could you dress the exposed bit of broken stud flat enough to center punch it, carefully drill through it and tap it 8mmx1.25, basically turning what was the hidden head of the bolt into a captive nut to receive a bolt from the outside?
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.