Primary O2 Sensors

[Dragon_ryder]

I have a 2K max Cali spec. Anyone know which two of the O2 sensors are the primary. I have four

[mtcookson]

I believe the two on the manifolds should be the primary sensors (before the cat).

[Beancooker]

Okay, I have talked to him on AIM about this, and to the best of my understanding, the problem is that the o2 sensors are not on the car. They're in a box in the garage. He needs to put them back in. This will require drilling new bungs into the headers. So on the top on the valve cover where the o2 plugs sit, which ones are the primarys?

[Dragon_ryder]

I'm trying to find out which connectors are the primary and which are the secondary. And they're right here on my computer desk lol