WUT? You mean Bubba’s great grandad George Wallace wasn’t a republican?
In 1865, blacks voted Republican. The started moving to the Democrat party in the 1930s thanks to FDR. By the mid 60s, they were about half Republican half Democrat. By the mid 70s, the vast bulk had moved to the Democrat party.
The "Great Society" programs probably had a lot to do with it.
The South was Democrat up until Reagan, and then it transitioned from Democrat to Republican in the intervening 40 years.