The F-4J was the last version produced for the USN and USMC. The “J” version was basically an upgraded “B” version with new radar and avionics as well as a better the “J” version is what isn’t there; the infrared seeker under the nose was deleted. Also missing was an internal gun but Sparrow and Sidewinder missiles were used for intercepting. Between 1966 and 1972 there were 522 F-4Js built. The F-4J had the distinction of scoring the only USMC air-to-air combat victory in Vietnam and it also was the last US operational aircraft in South East Asia. In mid 1970 the F-4 Phantom II was being replaced by the new and improved F-14 Tomcat.