its coming from the passenger header how do you seafoam it?well where does it sound like the clicking is coming from? you could seafoam it, or just pop the hood and rev it manually. you should be able to tell if it is in the headers region if it sounds like the noise is happening right there when you rev it manually - if it isn't from right there check where 95stangvert said to look
don't bother seafoaming it since you know where it is coming from. and did you use gaskets when installing? some v6s were built without gaskets but definately put one on if you didn't use them. either way make sure to torque it to 23 to 26 ft-lbsits coming from the passenger header how do you seafoam it?