Well, a bit of a rethorical question, but with some seriousness to it

.
With alt; no problem. B&Z til yer almost equal e, then disengange.
Co alt: merge, try to get nose to nose situation, avoid HO, run like hell, unless yer very low; then you can try to outclimb the P-51. Don't count on this to be a saving maneuver though. When 51 catches you, outscissor him, go nose to nose, run like hell. Repeat til dead or close to friendlies.
Alt disadvantage: Go for HO, then run.
The A5 has very little working for it against the P-51 - it has a higher roll rate at medium speeds, and a higher initial turn rate, dunno about acceleration, and climbs a bit better at low altitudes. The P-51 is considerably faster, has better high speed handling, and with flaps deployed, it outturns the A5; push the A5 and its wicked stall speeds characteristics will roll ya over towards the deck. Not sure about medium speed turn performance.
Reversing on a 51 is very difficult - you might produce a great scissors, but the 51 will either just leave you in the dust, or pop some flaps and spiral dive turn and will lose you. No go there.
With the N1K, that one can do a 180 turn and catch ya on the zoom, so make sure you hae a considerable amount of speed more before you try it. It'll easily outtrun you, and it'll defeat any snapshots by a hard break with relatively little e loss. Follow that turn for a snapshot for too long, and his 180 turn will leave him with enough e to catch you.
Situations against 4UC's are similar to the 51's - except the tsjhokk can defeat you in a turn fight much more easily.
Basically, these three planes are difficult to fight if you're in a 190. For me, the key has been teamwork and RW coordination (was fun yesterday kirin, those N1K's and 51's just kept coming

).
Of course, I won't reveal my secret fighting tactics against these planes (even if I had such

), but, I'd welcome input. Bot from 190 drivers but also from others more familiar with the weaknesses of allied planes.

.
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StSanta
JG54 "Grünherz"