Well the heat shield and cat weren't causing the noise, it's definitely piston slap. I recorded the sound on my cell phone. I don't know how well it translates, but you can hear the valves which is normal and then when I pick up the rpms you can hear the secondary noise which is the piston slap. Let me know if you can hear it.
http://s859.photobucket.com/user/rwl...74F34.mp4.html