A little more reading and you would've found that it was never used in combat.
Now I just found this on-line about the different P-51's.
P-51H (NA-126/129) lightweight version similar to XP-51F except longer fuselage, taller fin
V-1650-9A twelve-cylinder Vee liquid-cooled Merlin 1,380 hp /take-off, 2,218 hp/at altitude w/water injection
6585lbs empty, 9500lbs normal, 11,500lbs max
1380 hp @ takeoff , 2218 hp war emergency power @ 10,200 ft., 1900 hp @ 20,000 ft w/water injection
444 mph at 5000 ft, 463 mph at 15,000 ft, and 487 mph at 25,000 ft
5000ft in 1.5 minutes, 15,000ft in 5 minutes
Six 0.5-in wing guns
555 NA-126 s completed, 1,445 NA-129s cancelled
First flown by Bob Chilton on February 3, 1945, whether or not the P-51H participated in combat in World War II is still controversial
Here is the Site:
http://www.zenoswarbirdvideos.com/P-51_Variants.htmlThe first line says the H model was the same of the F model but with a longer fuselage
The last line on the spec. for the H model is interesting.
Enjoy