I am searching for Thomas Keown boen @1752 and immigrating to Sout Carolina @1774
Hi Kenneth,
Most roman catholic records were only started around 1820 or so. Some protestant records started around 1750.
However it's worth having a look at the following sites.
www.irishgenealogy.ie (free site run by irish gov)
www.rootsireland.ie (free to join and search, but pay to view record)
Hope this helps in some small way,
Anne Dennehy