Pretty obvious it was Johnson, and the last time a Democrat won the white male vote (or the white vote altogether).
Do we know for sure Carter didn't win the white male vote in '76? Remember, the gender gap was reversed that year with Carter doing better among men and Ford doing better among women.
That's obviously the only election since '64 where it's even remotely possible.
Huh, Gallup says that men voted more Democratic than women, but the Roper Center says that they voted the same. I guess we'll never really know, but its much more likely Ford did.