Tapping noise- Town and country 2004 /3.3
 

I have a upper end tapping noise on cold start up for about 1 to 2 seconds- maybe until the oil gets up there? I also noticed it when the van was warmed up and the idle lowered. Could this be a bad oil pump? Worn rockers?
I recently rebuilt the heads, replaced cam with a good used cam, new lifters, and timing chain.
Thanks