This isn't on my truck, but is on my 69 Cutlass. I have both tha A/F and the transmission temp.
The A/F is the Autometer Phantom one. Spendy, but I have all Phantom gauges so I wanted it to match.
I placed the sensor at the very end of the header collector. If I had it to do over again, I would probably move it a bit closer to the primary tubes. Even though I have a heated O2 sensor, it seems like at idle it cools off enough not to read after a while.
The meter is nice, but not necessary if you don't plan on changing things a lot. If you have a nice digital multimeter, you can do this with a cheap O2 sensor (one wire). Weld the bung in the exhaust and put in the sensor. Run the wire up into the car and then hook it to your voltmeter and run the car. With a non heated sensor, it will take a while, but soon you will see your voltmeter move.
The O2 sensor only puts out something like 1 volt max. But there is a chart somewhere that tells you what the voltages mean as far as lean or rich or stoich. If someone wants to go this route, let me know and I will scrounge up those documents. Once you get the carb and timing tuned, you can remove the O2 sensor and everything is clean again. Or leave it in and just hang the wire under the truck somewhere in case you want to use it for future use.
Since I am always adjusting mixture, timing, heads, etc, etc, I decided to go with the gauge just so I always have it. Makes a great conversation piece as well!
