exhaust studs

[InAccordance]

So as typical, the two lower center studs have come out with the nuts on them plus the thread stuck to it.
Digging through some old threads, there was a mention of using a standard 5/16 stud like this: https://www.oreillyauto.com/detail/c/dorman-autograde/performance/exhaust/exhaust-manifold-header-bolts---studs/1ae38bae6636/dorman-autograde-5-16-18-5-16-24-inch-thread-manifold-studs/dag0/675201?pos=8
The holes will have to be heilcoiled anyway and the guy in the thread says to coil it for a 5/16 stud as they are much cheaper and easier to obtain.
Anyone done this?
I kind of like the idea since those studs are super common.

Also, apparently the dimensions of the stock studs are 8mmx1.25x45mm, rockauto has replacements listed as m10x1.25x40 so which helicoil would I need if going with stock studs? I'd assumed the m10x1.25 set..

[conozo]

I have had three studs get ripped out so far. I fixed them with helicoil and re used the same studs but did get new bolts as they are the locking kind that need replaced once used.

Helicoil kit i purchased 5546-8 M8x1.25
Drill bit size 21/64
I also had to buy a right angle drill adapter so that i could drill the hole out with the bit and not remove the engine or anything from the engine bay to do the repair.

My studs ripping out was caused by a poor aftermarket exhaust system. Its just a cheap replacement stock bolt on kit but the hangers dont line up right and it was pushing the header toward the front of the car causing the bottom studs to rip out.