What could cause this ticking noise?

What is your question?

I have a '95 C1500 w/ a 350 that is ticking. I have normal oil pressure. Ticking comes and goes but usually always happens at startup. It only started doing this after I had the intake manifold gaskets and valve cover gaskets replaced and the oil changed. Didn't do any of it myself, had a trustworthy mechanic do it.