I found some more clues for you. There are 2 women researching Longcors in Michigan, but I have no idea how to reach them. I didn't copy their entire manuscripts when I couldn't connect my own line.
Virginia Starks wrote 26 July 1987 that her GGGfather, Gabriel (s/o John) and his wife Phoebe Mizner moved to Clinton Co. MI in 1866 from Van Buren Co. MI. They had 10 children, one of whom was James, a carpenter who built the Methodist Church in Shepardsville, while living nearby in Ovid.
Shirley Esperson wrote in 1990 that John (mentioned above) had two nephews Hirum Anthony (ss/o Henry) also lived in Clinton Co, MI.
It looks like you are probably decended from Gabriel, Hirum or Anthony. Let me know what you find out!