Power figures are listed below. 4700 fpm from 1750 hp at 7485 lb is not out of line with other WW2 planes for which we have similar data.
Merlin 66:
Normal Power, 100/130 Grade Fuel
MS: 1410 hp @ 2850 rpm, +12 psi, 8500 ft
FS: 1310 hp @ 2850 rpm, +12 psi, 18000 ft
Combat Power, 100/130 Grade Fuel
MS: 1750 hp @ 3000 rpm, +18 psi, 5250 ft
FS: 1625 hp @ 3000 rpm, +18 psi, 12500 ft
Combat Power, 100/150 Grade Fuel
MS: 2000 hp @ 3000 rpm, +25 psi, 5250 ft
FS: 1860 hp @ 3000 rpm, +25 psi, 11000 ft