Lifter tick (I think)?

Try a thinner oil grade like 10w30. That 20w50 may be a little thick for pumping up the lifters. And if it's a fresh engine it is even more so. Get it broke in good first with the 10w30 (500 miles) then you can go back to the 20w50 if you think you need to.

Adjustable rockers on hydraulic lifters? Try another 1/4 turn down on the valve adjustment to give the hydraulic lifters a little more preload.

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