I used a square magnet with a hole in the center made for drill bits. You put your drill bit in the hole then pull it out and it is magnetized. On the edge of the magnet is a de-magnetizer so you can clean the shavings off the drill bit. I took my time drilling the hole in the manifold, especially near the end. I would drill just a little bit, pull the drill out, de-magnetize it, clean it, re-magnetize it and repeat. I probably did that procedure 50 times, maybe obsessive but I did not want any shavings getting in there. As far as the engine running, I think it would be to hot to work on. Just take your time and you will be fine.

__________________
2008 Dodge 2500HD 6.7L 4X4 Laramie
Edge insight, Amp tailgate step, 4" Boss Bars, rear air bags with compressor, spray in bed liner