What do you guys think, am I going to have to split the cases again? Am I a fool for dreaming?

Personally, I would spilt the case so that there is no chance of getting shavings inside the engine. Good luck man!

I really hope it works for you, I've been in similar situations before and it's hearbreaking!

Good luck

It's just a helicoil, not the end of the world.

Good luck, dreamer ;)

If you’re going for it fully block it from the rear. start the hole with the tap in the photo and finish with a bottoming tap. This way you can avoid having the tap pass into the interior at all where it may drop chips