[Gunner]

I'd love to put an O2 port on my exhaust but I'm not sure what's required. I have coated primaries, so drilling and welding would be not-so-hot. Can I drill and tap a port right on the front of the #5 exhaust port, on the head? I have a nice clear angle there on the front corner but I'd have to look at a bare Performer RPM head to make sure there's nothing but metal in that curve. Would that be a functional place to put an O2 sensor, or do I need one on each side?