I have dynatech long tube headers with high flow cats.

The cats have 2 bungs welded in them (the front ones for the 02 sensors and the rear ones are plugged)

Just wondering if i can put my wideband sensor in the rear bung (after the cat)?

 

I did, but people say I screwed up cause it is after a cat. O well; readings look fine.

 

The sensor should be before the cats. I installed the bung just before the header to cat flange. There's not much room but it will fit.

 

I also installed my WBo2 in the rear bung of the cat

 

I was getting dynoed last night and the guy said too many people put the wideband behind the cats where the gas has changed form, hence catalyltic or catalist (change ).
Always put your air/fuel sensors before the cats !