So, here's the context:
My brothers, neighbors and I, played this game with 1/72 scale model aircraft in the 1970's and 1980's. We divided up the 9 acres of property we lived on (in the middle of all 3 families properties), designated oceans and came up with a set of rules about bombing, carriers, parents, and planes, to make it all work
As you can imagine, we had disagreements. When we had dogfights, those of us not involved were "witnesses" who were in charge of what was allowed/believable, and what wasn't. We could call a time out ("time stop!") during a dogfight, to argue our points about turning radius, altitude, climbing speed, etc. and implore the witness to agree with us, just as our adversary did the same.
We'd meet every few weeks, to talk about the planes and stats. We had to. The "witnesses" (aka referees) had to know which stats to apply. During a "time stop", the would back up or advance our frozen-in-space planes. They would explain to us who was faster at that point in the turn or climb.
As you can imagine, those meetings, about planes and stats...mattered a truckload.
We would bring books from the library. We would compare passages. We would vote and decide, which tome was most believable (based on evidence that supported it) and which wasn't.
I tell you ALL of this, to let you know how I spent about 5 or 6 years of my childhood.
..and to settle this debate....
Now, like anyone in this sort of circumstance, I'm ONLY as good as the info I was provided.
But trust me. As a teen, living on 9 acres of battleground, I f*cking did my homework. And this is what I remember most vividly about these two great American fighters. Of which I owned both planes, in various versions: (BOTH, P-51B, AND, P-51-D if you are asking

, as well as the F4U). And here was OUR gospel, voted on and agreed on, after much book-reading and comparing and correlating.
AFTER, WWII, according to the book we agreed seemed reasonable, accurate and in accordance with all of the other books we used for reference -- the Air Force did post-war fighter trials (I bet, to see which one to buy more of, as the era of jet fighters was arriving). And THIS is what I remember, from 1 or 2 books.
With American fighter pilots, at the controls, above (or below) 20,000 feet, the planes were considered equal.
And on the other side of that altitude (and I don't remember if it was ABOVE IT, or BELOW IT), the Chance Vought F4U was considered superior.
By American pilots.
Discuss.