Educate me on early A vs 67-76A

I have 75 disc brakes on my 1964 Dart so you can go to the 4.5 bolt circle pattern. I think the biggest issue with the early A's are the headers. Your options are fenderwells or TTI which I hear still have problems, spitfire if you can get them. Or you can spent 1200. and have a set custom made. If you convert the car to coilovers up front headers are easier to make work but these conversions for rack and pinion and coilovers are not cheap. Jayson