MicroSquirt.com read only forum (Jan.15,2018)

As long as the bung is located between the cat and the engine you should be able to use the same location for both wide and narrow. The only thing to consider is the heat range of the sensor you are using. For example:

"The Bosch LSU4.2 wide-band O2 sensor (shipped as part of the LM-1 kit) is rated ...