P-51D based on the Wright Field and Inglewood tests
5000 ft - 3575 ft/min and 390-396 mph (radiator shutter closed vs shutter open)
15,000 ft - 2975 ft/min and 409-412 mph
28,000 ft - 1030 ft/min and 434-439 mph
For comparison with British fighter of the same period
Tempest V (ADFU and Hawker Trials)
5,000 ft - 3,640 ft/ min and 405-412 mph
15,000 ft - 2,750 ft/min and 420-430 mph
28,000 ft - 850 ft/min and 405 mph
Spitfire XIV (ADFU and Boscombe Down trials):
5,000 feet - 4,650 - 4,870 ft/min and 382 - 391 mph
15,000 feet - 3,600-3750 ft/min and 407-416 mph
28,000 feet - 2,600-2,960 ft/min and 444-446 mph
Of the three:
The P-51D wins out overall in speed; more speed with less horsepower (1720 vs 2000-2050 for the Spit and Tempest). It had a very fast airframe.
The Tempest is clearly the fastest below 15,000 ft, but the Sabre sucked above that because of its very simple supercharging.
The Spitfire climbs like a lift. Its climbing harder at 15,000 feet than the others are at 5,000 feet. Sometimes there is no substitute for the small airframe, powerful motor, big wing combination. Fastest at high alt, but only by a squeak.