Accoring to wikipedia: "A large number of General Dynamics F-16 Fighting Falcon variants have been produced by General Dynamics, Lockheed Martin, and various licensed manufacturers. The details of the F-16 variants, along with major modification programs and derivative designs significantly influenced by the F-16, are described below.
...The Block 25 F-16C first flew in June 1984 and entered USAF service in September. The aircraft are fitted with the Westinghouse AN/APG-68 radar and have improved precision night-attack capability. Block 25 introduced a very substantial improvement in cockpit avionics, including improved fire-control and stores management computers, an Up-Front Controls (UFC) integrated data control panel, data-transfer equipment, multifunction displays, radar altimeter, and many other changes. Block 25's were first delivered with the Pratt & Whitney F100-PW-200 engine and later upgraded to the Pratt & Whitney F100-PW-220E. With 209 models delivered, today the USAF's Air National Guard and Air Education and Training Command are the only remaining users of this variant. One F-16C, nicknamed the "Lethal Lady", had flown over 7,000 hours by April 2008."