I guess, what Im trying to ask, Do you need a wideband tune after adding headers?

 

Good question. I think it makes it richer. Some one with experience will chime in.

 

If you leave the stock tune in you will have very high fuel trims. It will be leaned out.

 

When I did my ARH's and ORY a few weeks ago, I installed a LM-2 WB and found out that my AFR @ WOT was rich - ranging from 11.6 to 11.4 or so (depending on RPM).
I have an '08 Sierra Denali w/ the 6.2, stock cam, and a VaraRam. My friend who does my tuning says the LTFT's were very high and he thinks the ECM was overcompensating because the headers leaned the mixture out so much, but I'm not certain about that, because I never did a WB check before the headers and ORY. We have it at 12.5 or so now and still tuning...
You would definitely benefit from doing a W/B tune after the headers, IMHO. The Innovate LM-2 is really cool and I good value because you can also scan for DTC's etc.

 

thanx for the replies everyone. Im hoping headers lean out the tune for better gas mieage. I dont want to have to do any serious tuning until the cam.

 

I think you may be misunderstanding the answers you are being given.

Yes, the headers will be leaning the current tune out, but the pcm will be trying to compensate for that by dumping excessive fuel, so in reality you'll be using more gas until the engine is tuned for the new headers.

 

that sux