Looks like your problem may not be an easy one. I found posts going back 10 years with people asking the same question.
However, there are some ideas that may point you in the right direction.
First, Bluford Johnson was not born in Pike County, KY. Pike County was not formed until 1821. I suspect that Bluford was born in Floyd County, which was formed in 1798.
I suggest that you gather all the records you can find for all the members of Bluford's family and attach them to your family tree online. You should identify all of Bluford's children and find all their vital records and census records. You never know where the hint you need may be found.
I located Bluford in Floyd County in 1830, in Wyoming County, Virginia (later West Virginia) in 1850, in Nicholas County, Virginia (later West Virginia) in 1860 and in Clay County, West Virginia in 1870.
You indicate that Bluford died in Clay County in 1870, but I did not find a death record for him there. Do you know where the information about that death date and place came from?
Do you know who the parents of Nancy Smith were? She and Bluford may have lived near each other before their marriage and that might help you sort out early Johnsons of Floyd County.
Good luck with your search