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

[1948F-1Pickup]

I probably wouldn't use the Loctite product.
You didn't post a photo but I think your heliarc concept might be best.
I'm assuming you're not doing the welding. This is not something you want
to do yourself unless you're experienced in this type of repair..... the "learning
curve" is quite steep and probably fairly unforgiving.

And after your repair, I don't know if it's appropriate for what you're doing but studs,
rather than mounting bolts, are far more durable.