Charging Problems !!!

I just bought my first Mustang and just found this site. The Mustang has some problems that I'm having some problems getting fixed. Its a 94 GT that if I put it over 3 k then the alternator puts out over 19 volts. At any other RPM it sits at a solid 14.5 volts. I have replaced the voltage regulator, and the brushes while I was there. All of the wiring is solid. I don't think that the stator or the rectifier could be causing this, but maybe I'm mistaken. The other issue I'm having is with the headlights. If I have them for over 30 minutes, they blink on and off. I've checked the grounds and all of the wiring and it looks good. I'm going to replace the switch in the morning, so hopefully that will fix that issue. I also have some performance issues, but I need to get the alternator and headlights fixed before I dive into those. Any help would be greatly appreciated!!

Thanks!!