Please help with ticking noise

Well, it dont seem to be a rod knock, did the test with pulling plug wires one at a time, the ticking doesn't change or dissapear.
The strange thing is when I start the engine cold (over night) it's quiet, but after about 2-3 minutes on idle it begin with a couple of tick and after that it tick instantly, then after fully warmed up it tick but much quiter compared to under warm up. Exactly the same as before the top rebuild: (cold startup)Quiet->(under warmup)TICKING->(fully warmed up)ticking
But of course, if it had a worn out lifter before and one of the new one is crappy then it's no difference.
Non adjustable new stamped steel rockers.
New mechanical fuel pump.
I've always run this engine with 20/50 oil, maybe once it got 10/40 but no difference, I've tried Wynns Super Charge a couple of times before the top rebuild, but no difference, do you think I shoud go the other way with thinner oil?
Oil pressure about 45-50psi at idle.
I finally got the valve cover sealed without any leaks but I will pull them and start her up to see if I can figure out if there's something wrong.