I just thought i'd share my great experence with pyb. My 2003 silverado has been ticking for about the last 5000 miles and nothing i did would quiet it down. It would also seem to consume almost a quart every 1500 miles. I have used gtx in the past mostly. I switched to pyb after lerking around bitog for so long. It seemed a perfect fit for my 4.3 vortec. I have been running pyb 5w30 for the last 1000 miles and i love it! It has almost silenced the ticking sound, and has burned absolutely NO oil. I think i found "my oil" and for 15$ an oil change, i guess you cant beat pyb !!