This sounds promising.I have participated in the DNA project and my results are posted on the Allen Family DNA site.My earliest ancestor listed there is Josiah Allen (1796 - 1856) but I am now convinced he is the son of Rev. War soldier John Allen (ca. 1739 - 1827) whose 1st marriage was to Sarah McDowell, dau. of James McDowell and Mary Davies.James McDowell died in 1747 in Lancaster Co. PA and in 1751 his widow sought permission to move with her children to North Carolina.They came to Mecklenburg Co.
Sarah McDowell died in 1779 at age 32 and John then married Frances Brown, dau. of Patrick Brown, and had a new family.
John Allen was a shoemaker and was an heir to the estate of a James Allen (who died 1780/1) in Mecklenburg Co.Another heir was William Allen.This James was listed as a "planter" in Mecklenburg Co. as early as 1765.I am unsure if he is the father of John or a brother who had no children at his death.In any case, James Allen left a sizeable estate.James' widow married David Montgomery.
Do you see any family connections here?Could this William McDowell have been a brother of James McDowell?There are several McDowells in Mecklenburg Co. in the 1750s onward.