You started the thread with an assertion that is on the same footing as my speculation.
In 1976, after the South supposedly supposedly switched allegiance, shortly after LBJ's (reported) claim that he'd "lost the South for a generation", all the Southern states except Virginia voted for Carter, a Democrat.
(Apparently there's some doubt about whether LBJ actually said that. The media may have lied to us again.)
That Ford was closely associated with Nixon and had pardoned him? Why would the South have cared more about that than the rest of the country? Despite the pardon, Ford won 27 states, including California, and 48% of the popular vote.
In 68 much of the South voted for Wallace, a Democrat running as an independent, and Texas voted for the Democrat ticket. In 72 every state save MA and DC voted for Nixon, so the South doesn't stand out there. Then in 76 the South voted for the Democrat, Carter.
It's not until Reagan that we see the South reliably voting Republican.