The NCGenWeb is dedicated to free genealogy research. They are currently collecting resources on African-American genealogy.
Check out the following sites that are filled with rich information:
NCGenWeb site on African-American Special Projects.
Tom Blake’s Slave Data is one of the largest list of slave holders in 1860 and census for 1870
If you have African American research specific to McDowell County, please consider sharing with others.
Email and I will help you get your desired information online.