Re: Broken exhaust stud!
Ditto on the Allen head cap screws. There is absolutely no reason to use studs and nuts.
The Allen heads will clear the pipe and maybe even that sloppy weld at the pipe/flange connection.
As was already said, don't over tighten. Most of the time failed fasteners and threads are the result of over tightening, not "cheap material".
You will also benefit from lapping the flange gasket surface to get a good gasket seal. Almost without exception you'll find that flange warped from the welding process and that's the reason for exhaust gasket failure and leaks.
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