Improved F-4B version for US Navy and Marine Corps, with emphasis on air-to-air combat capability improvement, which include: J79-GE-10 engines with 17,844 lbf (79.374 kN) of afterburner thrust each, AN/APG-59 pulse doppler radar coupled with the AN/AWG-10 Fire Control System for look-down shoot-down capability, larger main landing gear wheels resulting in wing bulges similar to F-4C, slatted tailplane, ailerons drooped 16.5° when landing gear and flaps were deployed to decrease the landing speed, zero-zero ejection seats, expanded ground attack capability, no IRST sensor under the nose; One USN pilot and one USN Naval Flight Officer became aces in F-4Js. First flight May 1966; 522 built.