Ticking sound while engine running

Thanks for the advice so far. It's got stock exhaust manifolds. Took the video on my blackberry and since the mic is on the front I had the camera pointed the other way but moved it around the engine.

Was just out for a cruise when I first heard it about a month ago stopped at a light. The weather hasn't been great here but I went out last night and heard the same noise again. It's running smoothly (no miss) and making the noise. It does sound somewhat intermittent. I have a longer video that I didn't post where I varied the RPM's but it was too loud to hear if it still made the noise.