The A/F gauges that use the O2 sensor signal will jump all over the place. The reason is that the O2 sensors "switch" between .2 volt lean and .6 volt rich with a curve that looks like the drop off a high cliff. The curve is almost straight up and down, so the voltage shoots from .2 to .6 and back down . again 2 or more times a second at cruse. You won't get much useful information except when the mixture is extremely lean or extremely rich, there is no middle ground.
Use 43 (Dark Blue/Lt Geen wire) or pin 29 (Dark Green/Pink wire ) on the computer. Use Wire tap-ins from Radio shack P/N 64-3052. The computer is located under the passenger side kick panel. That keeps you from having to crawl under the car and make a weather proof splice in the wiring. You can use either one, or run a SPDT switch and use both. Then you can use the switch to select which side to view.
See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host)
Chuck, some WB's allow a stock O2 to be replaced (two birds with one stone) but almost everyone chooses not to do this. It's 10-30 bucks most of the time to have an exhaust shop weld a bung in for you. Then you have it mounted right where you want it and no where near 6 o'clock on the pipe.
Ok cool ... it came with the bung i was trying to get out on the "cheap". I'll suck it up and run it to a muffler shop. U think on the header or the h-pipe??
I'd go with the manufacturer's recommendations (some have stricter heat limitations tha others). If you have a heated WB O2, I'd error further downstream (towards the rear of the stock O2 if you have shorty headers. Just stay ahead of the cats and Thermactor plumbing, if applicable).
The left bank is generally the most widely accepted (it's supposed to be the leaner bank due to the intake).