Seeking emigration information for John Feathers

I have a good family history of John Feathers' lineage in America. But all the information the family has of John Feathers (1740-1790) is that he came from Ireland. His first born child in America was John Lawrence Feathers who was born in Albemarle County, VA. I wonder if John Feathers was part of the Ulster diaspora to the Appalachians where I was born and where 4 generations of Feathers (from John Feathers of Ireland) arise. I searched in the Ulster Historical Foundation archives but incompletely. They are conducting a search in their records for me at present. What early records, such as marriage and death records might the archives hold for John Feathers. He married Matilda Parsons from Pennsylvania. Thank you,