Help diagnose engine ticking I

[jd21476]

So I fired up my 350 today and let her warm up. I noticed there was a loud and very noticeable ticking coming from the passenger side of the engine. It almost sounded like the exhaust header was loose and leaking air.

Anyway I drove for a while to see if it got better or worse. After a short trip it seemed to have almost gone away but you could still hear it a little bit.

Any ideas?