[Mackpipes]

I have a miss at 5500 rpm at full throttle. I put in new plugs (with correct gap), new wires, cap and rotor. The rebuild has 2k miles on it. I just put in new crank and flywheel sensors, as well as a head temp sensor. The motor pulls hard up to 5500 and then stumbles slightly and then continues to pull up to 7000. I should add that I rebuilt the motor with Raceware rod bolts and head studs as well as Assco sport valve springs and Ti retainers. This symptom is intermitint. The miss happens every 3rd or 4th pull to redline. Where should I start looking?