that noise is probally your cam you are hearing. and if you have a exhaust leak you some times will throw a DTC saying low Voltage on O2 sensor.

 

I'm in the same boat. I have had headers in the past, but I was amazed at how loud the tick is with these. I have 1 7/8" primaries now and my old headers were a ceramic coated 1 5/8 on a 350, so I guess its a completely different ball game, but still.
I have checked a couple times for leaks and I can't find anything. Its frustrating, but like others have said, I learned to live with it already and I love the extra power.