Engine is a fresh build 4 1/4 stroker 30 over 4 bolt main all forged. air gap intake. brodix RR-O. hyd.comp cam XM278H holley 850 dp. log exhaust. Oil pressure is 55 at idle warm 75 when on it. I have about 7 hr on the build and after a 20 min cruise I start to get some lifter noise if you bring it back down to an idle after about 30 sec. the tapping will go away. At this point I have re ran the valve three time and not finding anything loose or out of adjustment. I have also pulled the Intake and inspected all lifters did not find anything.
And yes I have check for exhaust leak none found. Sounds like # 6 or 8 lifter is loosing pressure.
I am at the point of total frustration.
Should I just replace cam and lifters and be done ?

I has same exact issues. 5hrs on motor. Kept getting a ticking noise under load. Adjusted valves and nothing. Took it home,  removed intake, lifters, and cam. All still looked new. Pulled pan off and oil pick up screen was sitting on bottom of pan. Couple of mains and rod bearings where bad. Weird because still had good oil pressure.  I think I caught it just in time.

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