Yes it will work in a 64. I had heard that they did not get the center dash unit ready in time for the 64 production year and were using this unit to put A/C in a 64. Ronzo's brothers 65 has a unit in it. I have the installation instruction sheets available online if someone needs them to install the unit.
https://photos.google.com/album/AF1Q...tlEAr7O4SshMa5