There is a Vinson Willoughby (born abt 1854) in OHIO in the 1880 census, but no other individual is indexed by that name.
Searching on VINCENT Willoughby, I find the following individual in the Iowa State Census, 1895, for Louisa County, IA--his age places his birth at 1873: Name: Vincent Willoughby Age: 22 Race: W Birthplace: Louisa Co Iowa
I found a death announcement in the Burlington (IA) Hawkeye dated Feb. 5, 1880. Perhaps this is a grandfather for your Vinson/Vincent:
"Wapello "Vincent Willoughby, an old citizens [sic] of Toolsboro, this county, aged 60, died of pleurisy last night."
There is also a Vincent Willouhby of the right age living in Illinois in 1880:
Nancy WILLOUGHBYWifeMFemaleW24INKeeping HouseOHIN
Snala A. WILLOUGHBYDauSFemaleW9MILOHIN
[1880 US Census, Butler, Vermilion, Illinois. Family History Library Film 1254254, NA Film T9-0254, Page 218C]