Just wanted to throw this out there - picked up a 3" elbow off bing and quickly leaned about the skinny o2 sensor issue lol
Figured it would be a complete mystery, went to a local auto parts store (b&b dixon) picked up a brass “fluid flow pipe bushing” 3/8 x 1/4 is labelled on the case, $2 for a box of 2, fitting threads into the elbow, o2 into the fitting
I snapped a pic on my phone just don’t feel like uploading it on to the computer right now- if anybody is more curious pm you’re number and I can text you a picture of exactly the part and package
Cheers