stock exhaust header question

[rug]

I need to install an o2-sensor in the stock exhaust header for my megasquirt. Before I start drilling I want to ask a question, what is inside under the part that is raised up where the 2 pipes join into one? (Circled bellow) I need to put the bunge where this raised part or it will not fit under the car and I am hoping that there isn't anything like a partition inside that will ruin my day. I figure this raised part is just to give the metal som extra stability?



/Carl

[rebar1111]

I don't believe there is anything in there, but make sure you are far enough downstream of the 2 to 1 joint to insure a near continuous gas stream. The closer you get to the head the more isolated the cylinders are from each other and the more they will send a pulsed signal.
I found this out when I installed an O2 sensor in the 2 section of a 421 system. Had to mentally average out the actual reading.

[rug]

Thanks rebar,

Drilled it and it is all empty like you said I made the hole in the "1"-section so hopefully it will be fine.

Off to get ny o2 bung welded!

/C