I have the same cam in my motor and the same issues with a couple noisy lifters when the engine is warm and run awile. I have adjusted the preload about 3 times with no change and have spoken to Tim about it and told dont worry it`s fine. I have about 3000+ miles on my cam and the noise has not gotton any worse with mileage being put on the motor. Actually have about 1000 miles on the plugs in it and the motor still put out 540hp/538tq at the wheels on a chassis dyno a couple months back. So I would say button it up and drive the wheels off the car that is what I do.