Where is the stock O2 sensor located on an 85 IROC? The PO installed what looks like home made headers and put the O2 sensor bung on the tube for #5 cylinder right below the turn from horizontal to vertical (if I measured this with a string, it would probably be 4 - 5 linear inches from the port on the head).

 

In the driver side manifold.

 

Is there a location that would be better than where the PO put it? Down at the end just before the ypipe seems like a better place but if I could put it in the ypipe right in front of the cat that would seem ideal (and a little easier for me) .

 

you can move it down further, but you may need to switch to a heated sensor in order to get it to read properly

 

alright, thanks.