Ok, I am going to replace both my oxygen sensors. I currently have Dynatech Long Tube Headers but I am switching to LPP Long Tube Headers. I have O2 Sims on the back 2 sensors but I need to replace the others.

I looked up the AC Delco Sensors and it says:

AFS123 Heated Sensor (Position 3) Post Converter - I know I dont need this one but then it says

AFS123 Heated sensor (Position 2) Pre-Converter - Looks the same and has the same part number but is for a different position? Then there is

AFS75 Heated Sensor (Position 1) In exh manifold crossover

Which of the AS123 and AS75 do I need?? What is the difference in the positions?? Just trying to educate myself here lol

 

damn, whats up with noone selling AC Delco O2 Sensors anymore??!! I cant find any anywhere other than the dealer! Redonculous!

The stores here only sell NGL, Delphi, Denzo, and Bosch.

I WILL NOT use Bosch, but anyone know anything about the other 3??

 

The front O2s are AFS75's. That is what you want.

 

Thanks