A stripped hole is around 10mm, which is the drill size for an M12 thread. I cleaned the hole with a 10mm drill bit, then tapped it to M12 x 1.75.
Then I got an M12 bolt from Bunnings and cut the shank off (I cut it a bit short but that is ok).
I tightened it up with double nuts and then used a die grinder to very slightly enlarge the hole on the exhaust flange so it is easier to put on.
![Image](http://i.imgur.com/KvaHZF7.jpg?1)
![Image](http://i.imgur.com/Cbg0Xrh.jpg?1)
Looks like it will last and won't end up destroying the hole like helicoils do.