I had them weld the second o2 sensor bung in.
I have not had any trouble with wideband o2 sensors (other than innovate ones). I put 30,000 miles on my AEM one before it died. It was mounted horizontally (in the racing beat location).
If my O2 sensors die, I will have a good idea what caused it.
Logan: Maybe future headers (with the O2 bung in the collector) should have 30 degrees or so above horizontal.
Anyway: I finished Port-matching the headers.
At first I was going to try to port match to a set of spare junky housings that I had lying around, but this proved to be only a decent clue of what was needed, not really a good idea.
Here are a few pictures of what I found:
It was just about as hard to see what was going on in rear life as it is in the picture.
So I decided to build a cardboard template:
As the exhaust gasket clearly won't work:
I never ported the Racing Beat headers because they were beyond hope:
This picture shows the carbon traces from the brief time that these headers were attached to a running engine:
This shows the intended porting. As you can see, the headers have plenty of meat for porting, especially because the header tubes are inserted and welded at the outside, decreasing the risk of leaks from porting.
This is after porting the rear header:
Completely ported:
Turned out Ok! I suspect that this will help flow considerably.