Portable Air/Fuel Ratio meter

The Bosch WBO2 sensors are warmed up electrically and the Innovate controllers show this process and then switch over to the AFR or Lambda when its ready. It takes about a minute.

The distance up the tailpipe depends on the engine and the exhaust flow.
A car with a large diameter exhaust is going to have atmosphere pushing up the tailpipe or collector when the volumetric pulses are slow and less frequent. Shouldn't be an issue on a stock '67 273, but at idle, for a number of reasons, AFR from WBO2 always should be considered suspect and at the end of the tail, even more so.

I have that adapter and one issue with use can be the tailpipe's turndown. It just won't go in all the way to the clamp.