The Navy flew the F-4B extensively in Southeast Asia and as technology improved, the Navy ordered the F-4J to replace the F-4B. The F-4J featured an improved radar and higher thrust J79 engines. When Secretary of Defense McNamara's mandated replacement for the Naval F-4 faltered in development (the F-111B), the Navy performed a life extension program on their fleet of Phantoms. The F-4B received avionics updates and the resulting aircraft was designated F-4N, while the F-4J was not only given upgraded avionics, it also retrofitted with a similar flap/slat system as the later block USAF F-4Es. These updated F-4J aircraft were designated as the F-4S. These upgraded Phantoms soldiered on until the F-111B replacement, the F-14A Tomcat, could enter the fleet in sufficient numbers. A few years ago, Academy released the first new-tool 1/48th scale F-4 Phantom II kit in well over a decade and though many were skeptical that it could be better/more accurate than the Hasegawa 1/48 Phantoms, it turned out that Academy did indeed prevail. Since that time, Academy has released the F-4B, F-4C/D, and F-4J kits, all with great response. When Academy announced the F-4 in 1/72 scale as well, folks have been anxiously awaiting Academy's first installment in that scale. Your wait is over.