Knocking sound, please help

[stang2b]

I have an annoying ticking sound at about 2000-2500 rpm, doesn't make that sound before or after those rpms. I run 93 octane with NOS octane booster, some its not the gas. and it doesn't knock at lower or higher rpms, so its not a rod. What else could it be?

 

[five_o_stang]

do you have an o/r H-pipe?...for a while I thought my car was pinging around that rpm range...but it turned out that it was my h-pipe resonating...just a thought.. hope ya figure it out.