If you are looking aftermarket, then follow the suggestions from the members. Otherwise, if you are looking for a cheaper way to have front discs for an E-body, you can replace them with discs off of a 73-76 Dart. You will have to replace the entire brake setup including the spindle on each side (I also suggest the master cylinder). Some people may or may not agree with me, but thss is what I did on my 71 Challenger and I love them. The design does not look all that strong, but trust me after I have had to slam on the brakes multiple times to avoid an accident or other problem, I trust that the design is good.
Also the advantage to using these brakes is the fact that you can go to almost any parts store and find a replacement part without to much trouble. They are also cheap to replace. The only problem I have found is that the rebuilt capliers do not always have the same size piston and may need a little searching for a perfect match.
Hope this helps.