I found a James SHEPARD living in Enid with a 1943 birthdate. I will send you offline the address and phone number, as this is a very public forum and I dislike exchanging contact information on the boards about living people.
You say you have "records" about James' father's death and that he had a sister. Yet you say your birth mother might have made up the surname. Are you certain that the "records" you have contain accurate information?
Might they offer you further clues that you could share here? For example, do you know a name of your birth-grandfather or WHERE these people lived?
Voting records are available to the public at any election board. Birth and death records are available from Dept. of Health in Okla. City. Have you looked for traffic, family law or civil cases on the TWO court databases online?
www.odcr.com/ and
www. oscn.net/
I wonder if the surname SHEPERD is correct. There are so many variations of that name and misspellings are common. Just a thought...
"Treepig"