I don't know about your John C or Thirza, but there was a Hiram C.8 Lockwood born 7/13/1829. His lineage was Jeremiah7, Timothy6, Timothy5, David4, Robert3, Jonathan2, Robert1 Lockwood. His parents were Jeremiah Lockwood b 1/21/1785 and Hannah Arnold (b. 8/8/1775 d. 3/08/1835 MI). His grandfather Timothy Lockwood was born about 1763 in Dutchess County, NY. He enlisted at seventeen, served in Washington's Life Guard, and was a drummer boy at Valley Forge.
The only other Hiram Lockwood I know of was Hiram Leland4 Lockwood(Timothy3, Benoni2, William1), who was born 3/03/1814. His father Timothy was born 7/28/1788 in Springfield, Windsor, Vermont, and died 12/15/1865 in Springfield, Windsor, Vermont.He married Abigail Tobey 1/10/1811.