Poor white-black cooperation in Southern Republican parties was still very high until the counterrevolution of the mid 1870s, so there's really no reason to assume that, at least white yeoman, wouldn't be voting for Grant, too. The Gentry had basically lost it's right to vote (as well it should have), but it would be interesting to find out how the white vote did split, given the empowerment of white yeoman and black freedmen by the radical Republican parties of the South at the time.
I did say mostly Greeley, not all. Looking at the numbers, and how black the state was at the time (59%), suggests that there was a lot of white people voting republican too. However, those same white people would also be disenfranchised later along with blacks.
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