wuzak
Captain
This is what i can find. Nevertheless, if R-R Merlin 100 as installed, delivered maximum HP of 2080 Hp at 22,800 ft that will make it significantly superior to V-1650-9 since V-1650-9 can only deliver 1790 Hp at 22,700 ft, which make it 13% weaker. No wonder P-51H is so much slower than XP-51G
The V-1650-9 is, to all intents and purposes, a Merlin 100. There are detail differences, such as a slight difference in supercharger gear ratios due to a different gear train design.
drgondog told you that the higher power was with PN150 fuel, while the lower number was with PN130 fuel. The PN150 fuel allowed 80inHG MAP against 70inHg MAP for the PN130 fuel.
The V-1650-9 also had ADI, which the Merlin 100 did not, this allowing 90inHg MAP and over 2,200hp (lower altitude, though).