’92 Accord EX coupe o2 bung question

Hello!

I am in the process of installing a new header and downpipe and was wondering if it makes a difference if I put the o2 sensor in the bung in the header, or if I have to put it at the bottom of the downpipe right before the flexpipe. Long story short, I have the header installed, but I’m going to have to cut out the downpipe back to cat because it’s been welded and not bolted to the flange as I had anticipated. The old o2 is at the bottom of the downpipe, but there are 2 bungs available. Does it really make a difference where I put it considering that both are upstream locations and we’re talking obd1? Thanks in advance!

-Shan