From a huge list of F-4 models in

http://www.secretprojects.co.uk/ebooks/McDonnell%20Model%20Numbers%20List.pdf a few interesting ones.

**98CK** F4H/ADC Advanced Interceptor with AN/ASG-18, 2 GAR-9, F4H wing with widened center section, F4H tail, longer (69ft 10in) fuselage, J93 engines (1960)

**98CN** F-4H/ADC Phantom IIG Advanced Interceptor with AN/ASG-18 - wing and tail area inceased 20%, longer fuselage, two primary GAR-9, one alternate GAR-9, J93-MJ 252F engines. b) a 4 GAR-9 variant. (1960)

**98CP** Phantom IIF, as above with J58 engines (1960)

**98CR** Phantom IID, TF10A-20 engine (1960)

**98CS** Phantom IIE, J52 engine (1960)

**98CX** F4H with 700W Hughes coherent pulse-doppler radar, GAR-9. (1961)

**98CY** F4H with WECO 2000W coherent pulse-doppler radar (2 target track capability), 2 x Eagle AAMs, 6 in nose extension. (1961)

**98CZ **F4H, WECO 2000W coherent pulse-doppler radar, Hawk (Kestrel) missile system. (1961)

**98DD **Improved F4H with 700W Hughes coherent pulse-doppler radar, GAR-9 (1961)

**98DO** Improved F-4C with ASG-18, 4 GAR-9, TF-30 turbofan engines. (1963)

**98FG** F-4B VERY ADVANCED - 600 sq ft wing area with slats and double slot flaps, 119 sq ft tail area, AWG-10 with multishot Sparrow & Phoenix, SPARM. Nose lengthened 18", aft lengthened. (1964)

**98FH** As above with TF-30 engines (1964)

**98FI** As above with RB168-25R engines (1964)

**98FVS** Variable sweep, medium high wing (1966)

**98KU ** Navy advanced interceptor, F-4J modified AWG-10, Sparrow III and AIM-47 (1967)

**98LD/LE/LF **F-4J with AWG-9, Phoenix (1967)

**98LK **F-4J with enlarged wing, Phoenix (1968)

**98LL/LM/LN** F-4J with AWG-10, Phoenix (1968)

**98MC** F-4 for ADC, AWG-9 or ASG-18, AIM-47B (1968)

**98MQ** F-4E with F-15 systems (1969)

**98MS** F-4E with F-15 wing (1969)