The Intel Core i7-960 processor needs the FCLGA1366 socket. The DH55TC has the LGA1156 socket. I think that the i7-960 has 3 memory channels so it needs more pins...the i7-860 has two channels.
The compatible processors for your board are listed here: http://processormatch.intel.com/CompDB/SearchResult.aspx?BoardName=DH55TC
The socket specifications and other details of each processor is here: http://ark.intel.com