Stripped threads in valuable intake- Time Sert vs. TIG and redrill or other

[Mart]

If the holes have plenty of solid metal beyond the end of the thread you could drill deeper and tap the holes deeper. Then put the studs in, making sure the UNC end is long enough to get well into the new threads. And then make sure you are respectful of the threads and don't overtighten the nuts.
Why not even mention helicoil? They need less material to be removed than timeserts or other inserts. The helicoiled thread is stronger than a non helicoiled thread.

All these holes take studs. Once fitted they should never have to come out. It makes you wonder how they came to be stripped.

Mart.