2001 tahoe valve train noise

[tazdev001]

iv'e got a 5.3 ls in a 01 tahoe that has a lot of lifter noise and i am lost. i just replaced the heads, cam, lifters, oil pump, timing chain, water pump. i have 80 psi oil pressure at start up it drops to about 70 at orp. temp and it still has that ticking noise what could it be? what am i missing?

[Rmiller11]

Maybe a exhaust manifold leaking that will sound a lot like the noise.. maybe run some atf in the oil then change it. I put 1 quart atf in run it a day or two then change it. Either that or diesel. May have some trash causing a lifter not to pump up..