Ok i just read through and i see you fixed the problem but id like to throw in my. 02 cents on the timing chain...

Id recommend doing it...it cost about $75 for chain/grears and gaskets/coolant..and about 4 hours to do...i did mine at 203kthe cuz i didnt know if it had been changed...truck ran great but better safe than sorry...when i pulled the timing cover the chain looked great...but when i touched it the chain was so loose i was almost able to pull it right off the gears and my truck had no odd sounds or any motor problems...im just trying to tell you its better safe than sorry and its easy as hell...hardest part was pulling the harmonic balancer off...

And i didnt do top dead center or anything....i just pulled the old chain off and put the new chain on just making sure the punchmark lined with the silver link at 12 o clock on the cam gear...the gears are on keyweights so they only go on one way so just make sure the chain is in the same position as when it came out...seriously a very simple job....and worth it...my truck has 228k and runs like a top...engine doesnt ping/ or shutter at all...rpms never bounce around and oil psi is always above 40psi....but i also put in the highest quality parts/fluids i can...

As for seafoam....honestly i noticed little to nothing...and when i did my plenum afterwards the engine wasnt any clean then from when i pulled the intake the first time...but my motor was still clean....so in my opinion seafoam is a waste of money....

Also how hard was it to remove your header? I havent done one before and i need to pull my right one to get my egr pipe off...

 

Okay, thanks for the confirm. I wasn't sure if that was pinging, just thought it was normal, I always thought ping would be more of a knock sound.