clacking noise consistent with engine speed on hard acceleration

my tacoma has been making this noise for a while now its getting very annoying..whenever i accelerate fast it will make this clicking/ticking noise that is consistent with engine speed...recent mods include headers a couple months ago and then just recently swapped my AT2525 out for a flowmaster 40 series...i think i noticed it more after the new muffler anyone know what it may be?

 

Bump..come on anyone

 

If your header is leaking it will make a ticking or clacking noise with every exhaust pulse (depending on how big the leak is), and that noise could be quite loud, especially if it's leaking at the head flange. Since you just did a bunch of exhaust work, I'd start looking for that. If it got louder switching to the Flowmaster from the less restrictive AT2525, that's a pretty good hint.