Proper Exhaust Stud and Nut Size!!

[Pitts]

Alright, so I was putting my exhaust back on today (almost done with the tranny swap). I had ordered a whole new set of exhaust studs and nuts as 4 of my old ones broke. Everywhere it says the size is M10x1.5 and 62MM long. RockAuto, local part stores, everywhere. I always thought they were a bit big but never verified until today. As I go to install them, I noticed they were quite massive compared to the threads. I ended up finding out that they were M8x1.25 and 50MM long after a long phone call with my local GM dealer and testing with a thread restore kit. So after calling around my town, I found some bolts that would do the job from Fastenal. They were a bit long, but I made them work using a washer, locking washer, a 8MM nut, and a 10MM nut (from the exhaust stud kit). Still managed to hide under the heat shield without modifying the shield. So if you have to replace the studs, don't trust what everyone else tells you, call GM or figure it out yourself. Between the heli-coil kit, the studs, and shipping, $80 down the drain all because no one decided to have the proper part.