The earliest census substitute in Ireland is the
Tithe Applotments 1823-1837:
The only Sloan listed in Cork is:
George Sloan, Parish Cloyne, Ballycottin
Your George Sloan would of been 77 by this time.
Depending where Cloyne is located as to finding birth records can come from two sources for Cork:www.irishgenealogy.ie
and an Irish History (not for profit) Foundation who has the records for the North West side of Cork. This Parish of Cloyne has RC records for baptisms from 1791-1922 and marriages 1791-1895.
British Navy records were available through the National
Archives at Kew, England and they have permitted a genealogy websitee to put the records on line. At a cost of course. The link is on the Archive website.
Griffith Valuation 1847-1864, Cork 1853.
10 Sloane's in Parish Cloyne, 8 Townland Ballycottin, 2 in Islands, all Poor Law Union Middleton, Cork www.askaboutireland.ie
Mary, 4 x John, 5 Phillip.
George Sloane, Parish Templerobin, townland Carrignafoy,
Poor Law Union Cork, tenant of Wallace Cotterell
#8 Lower Cotterell's Row