God Forgives I Dont

I have noticed sense I got my Headers (Pacesetter LT) and Cam (CC 228/234 588/598 112) installed that my car is shifting a lot sooner than it used to at WOT (stock 5900+/-, after headers and cam install 5600+/-). I've even gone in with my Predator and set the shift RPMs up to 6200 and Rev Limiter up to 6400 to see if it would even Rev to redline and it is still shifting too early at somewhere around 5600RPM. It doesn't seem to change anything when I modify either the shift MPH or RPM. I checked Tran’s fluid and it’s full and I had changed it not to long ago so it should be good. Stock torque converter is still in place but I installed an ES Trans mount with ground bumps due to bad vibrations. Anyone else notice this happened to there car? Or have any educated guesses on what the problem is? Thanks Guys