Header Install Question (part 2)

[Colin Cox]

I finally took the secondaries to a muffler shop, and they quickly removed
the AIV tube (sorry, I initially thought it was the EGR tube) for me.  I
got back home thinking all was well, and discovered that I had the O2
sensor in the wrong place.  The AIV tube goes in the lowest hole at the
junction of the # 3 and # 4 runners.   My problem now is that the O2 sensor
won't fit in the hole on the side of the # 3 runner, it's too big or the
hole is too small.  The fittings on my EGR tube, AIV tube, and the O2
sensor are all the same (about 1" diameter).  So the plug they provided me
was the AIV plug.  So now I'm wondering is the thread diameter of the O2
sensor supposed to be smaller, and I somehow have a bastard O2 sensor?  Or,
should all of the holes be the same diameter, and Hotshot somehow welded in
an incorrect bung?   Trying to get the car running by Monday!

-Colin
'93 NX2K