Just a FYI...

I noticed a bit of extra noise coming out of my engine bay, a few moments after it's started when cold.

For the heck of it I threw a (13mm) wrench on the header bolts, and had 5-6 of them that were mildly loose. I've never touched them, and the truck only has 24K on it.

Supposedly torque specs are 11ft/lbs from the center bolts out... then a second pass using the same pattern to 18ft/lbs. Some people go as high as 22ft/lbs.

I didn't exactly torque mine to spec, just snugged them up, and it seems to have cleared up most of the noise.