The Protestant vote collectively has always been majority republican, the Catholic voter collectively has almost always been majority Democrat, the black vote switched in 1936, not in the 60s.
Aside from blacks there hasn’t bee a real shift in the voting of the groups, except that Catholics are less consistently Democrat than they have been, but that will probably not last for long Reagan was probably the high point for the Catholic vote in America.
I see. So if a trend doesn’t conform to your prejudice (Catholic voting rather than Southern voting), it is a simple aberation that will switch back, and if it flat contradicts your general theory (black Protestants) you throw it away as inapplicable.
“Lies, damn lies, and statstics,” indeed!