[bad466]

Getting ready to start putting my drivetrain in and want to have my headers ceramic coated. Where should I put the bung for my o2 sensor, in the collector or the exhaust pipe?

 

[allend43]

I prefer the collector of the header, just in case there's a leak at the header to pipe connection, which would throw off the readings.

 

[Greg Kelley]

If this is a race only piece with open collectors, I would recommend in a primary tube (12-15" from the head). With open collector you get back pulses of clear air which gives false lean readings. Also some collectors leak where the primaries slip in.

At this point do both and you are covered. Put one in each collector and one in #1 and #8 12-15 inches from the cylinder head.

 

[68Bird]

I agree with Greg. But if you happen to know what cylinders run the leanest you'd be better off adding a bung to one of those instead of a random cylinder.

 

[tomato]

Collector. Not much going on below 2000 rpm.

 

[bad466]

Thanks guys, looks like I will put them in the collector.