Fact sheetsGo down to F-4s and check their performance.
CAP for a D:
PERFORMANCE for Combat Air Patrol (CAP) Mission:
Four AIM-7 Sparrow missiles, one 600-gal. and two 370-gal. external tanks
Combat altitude: 40,000 ft. maximum
Combat speed: 1,178 knots at 35,000 ft. maximum power
Combat weight: 36,140 lbs.
Combat radius: 250 nautical miles
Mission time (CAP): 2.48 hrs total; 1.39 hrs CAP
(the Combat speed would appear to be the combat MAX speed, and the 2.48 hours total would appear to be where most of the flight is cruise at about 550 knts, since the following is given for the F-4C)
PERFORMANCE:
Maximum speed: 1,400 mph/1210 knots at 40,000 ft. maximum power (ferry mission)
Cruising speed: 590 mph/546 knots at 35,000 ft.
Range: 1,750 miles/1528 nautical miles ferry mission with one 600 gal. and two 370 gal. external tanks
Service ceiling: 59,600 ft.