Front Drum brake troubles on a 1964 Dart

Hello I bought a 1964 Dart convertible where every time I hit the brakes after about 10 minutes on the highway it starts vibrating violently. The previous owner said that he had just got new drums for it. I think he sold the car because the new drum brakes were warped. Does anybody know a good place to buy good new or NOS drums? I read someplace that the newer drums aren't as thick and warp easily.

Any help would be greatly appreciated!
thanks,
-Paul
This is your second thread you have started about your brakes. You only need 1. Check around at machine shops, older car repair shops and parts stores and have the drums turned. If they are discolored and have been overheated you have other issues. By the way, Drum brakes and brake drums are 2 different things and pads are for disc brakes. Drum brakes have brake shoes not pads.