360 Magnum with stock EFI engine codes

napa has o2 bungs. also there is a kit out there that basically eliminates the ds o2. or like a teacher at school said, " just tie the down stream o2 up out of the way and it will be okay." several have tried it and no problems so far.
My issue is I don’t recall a plug on the harness for the o2 sensor and I don’t know what wires to splice into to make it work.