Hello aghadowey!
I think you've found him!

Thank you so much!
Protestant is the correct religion as far as my information goes. Also, I checked a file I just received from a cousin of mine who is researching this man and he has down for John's father another
John McGaffin and a
Mary Beth Bingham as his mother, so the Bingham family works.

It was suggested in some family lore that John left Ireland because of a break with his family. The story was that his father died, his mother remarried and he never got along with his step-father. Perhaps, if he was living with his grandparents, that bit of lore may actually have had some truth to it!
Do you think I could beg you to do a bit more digging and see if you could verify some of that?
Thanks again - you've been a big help already!
Tam