Thanks to the input of Xenocrypt, I was able to get my hands on election data that allowed me to create the map for the 1964 Presidential Election, Results by Congressional District:
Isn't it beautiful? :D :D :D
This leaves me with one final map. The epic prequel to 1964, the 1960 Presidential Election by Congressional District. Although I was able to get a hold of some of the results, there are still a lot of empty spaces:
This map was drawn by Atlas Forum member realisticidealist.
See what I mean? I have basically no data on urban areas like Chicago, Detroit, Cleveland, Pittsburgh, Philadelphia, New York, etc etc. If anyone knows where I can find said data, I would be very, very grateful. Thank you!
-Fuzzybigfoot