Disaster. Let someone do it whos done it before. Seriously, I tried it. All the right tools...center punch, 21/64 tap, 1/8-27 NPT tap, good drill, WD40, helpful hands and everything. Bad decision for making the hole in the boss for the heat shield...Use a thinner part of the manifold.

I cracked the piece threading it in after a huge struggle tapping it with the engine on. I plugged the hole with a 3/8-16 tap and bolt, JB welded in. Doesn't leak. Im going at it on Sunday, if anyone has any suggestions for easier placement with a pictire.

 

Thanks for the input.