PPP has an interesting poll of Mississippi Republicans. Here's a taste:

We asked voters on this poll whether they think interracial marriage should be legal or illegal- 46% of Mississippi Republicans said it should be illegal to just 40% who think it should be legal. For the most part there aren't any huge divides in how voters view the candidates or who they support for the nomination based on their attitudes about interracial marriage but there are a few exceptions. Palin's net favorability with folks who think interracial marriage should be illegal (+55 at 74/19) is 17 points higher than it is with folks who think interracial marriage should be legal (+38 at 64/26.)

No. This is not from the 1967 archives.