Hello BITOG,
I thought it would be helpful to pass on how I significantly reduced my lifter tick on my 2004 5.3L Tahoe. Here is the history (I picked it up with 160K miles, 1 owner):
0w40 Mobil and Purolator filter - First time I noticed ticking
5W30 Pennzoil PYB and Purolator - Ticking became noticeable at 2000rpm and up
5w30 Pennzoil Platinum with PF61E filter - Ticking like a boss at all RPMs (sounded like an exhaust leak)
Removed valve covers and sprayed B12 Chemtool down pushrods, soaked for 1 hour (no change)
And my final solution turned out to be pretty cheap:
5w30 Mobil Super High Mileage with Rislone Engine Treatment Concentrate and PF61E filter!
I'll probably use 10w40 Mobil Super HM this summer, although I'm very happy with the results so far. I had tried Seafoam in the oil and I'm sure it helped clean the engine although it had no effect on lifter noise.