That is information I don't have but I don't think hardly any switched. They simply lost support from southern Republicans and were voted out.
One example is in the article...
"Goldwater Republicans fought them for control of the party and ultimately won, driving out many of those civil rights supporters. (Most dramatically, Senator Thomas Kuchel of California, a prominent liberal Republican who co-managed the bill in the Senate and refused to back Goldwater in 1964, was successfully
primaried from the right in 1968.)"
Also from the same article...this is startling.
That same convention adopted a platform that significantly scaled back the party’s previous support for civil rights. You can read them yourself and see the progression — in
1960, Republicans had a lengthy detailed section on civil rights with an aggressive agenda; in
1964, just a few vapid lines; in
1968,
not even a mention of “civil rights” at all. (At the state level, the shift could be even more dramatic. In 1964, the Mississippi Republican Party’s platform
stated: “
We believe in separation of the races in all phases of society.”)