I'm apparently missing something and it's driving me nuts. How exactly do you know if you need the flat 4 pin 02 sensor extension as opposed to the square one? I have a 95 z28, single cat, automatic. I'm looking to get my headers on and everything but I want to make sure I have all the appropriate gear.

Is this a case of certain years have certain shapes of connectors or do I just need to yank one out and see which it is?

 

Flat.

 

Sweet, thanks man. This has been driving me nuts and I've been searching for like 20 minutes though old posts to no avail.

What uses the square connectors then?

 

NP.

Post-cat / Rear O2's on 96-97 cars are the square connector.

 

Ah that makes a world of sense now. Much appreciated.