Exhaust Manifold Stud Issue

[LKap]

My issue is the stud location where the manifold meets the exhaust pipe.  When I took it apart there was no stud in there, just a 3/8" course thread bolt. I think the manifold may be stripped because I got a new 3/8" stud and it won't thread - just spins in the hole. 
2 Questions:
1. What is the correct stud size?
2. What are my options if the hole is stripped? I don't really want to replace the whole manifold. Can I drill/tap for the next size up? What about a coil-type insert?

Thanks in advance!

[specialty]

Not positive but I think it's a 3/8 stud size. I had the same issue. You could just go to a 7/16 stud. You probably won't even have to drill it since a 3/8 bolt is almost the same as the drill size needed for a 7/16 thread. You could also go with a Heli-coil but more expense required for the coil and the tap unless you happen to have it. Good luck.

[LKap]

Good to know I'm not alone!  I think I'll try to tap for a 7/16 stud and see what happens.  Worst case scenario if I screw it up I can always do the heli-coil.  Is there a special tap for the heli-coil? I've never used one before.

[specialty]

Yes, a Heli coil uses a different tap. I had one that broke off and one stripped and the 7/16 tap did the job.