There's a reason why one Bearcat or another has held the world record for time to climb (standing start to 10k feet in 96 seconds, IIRC) for over 60 years. The F8F is wheels up and long gone before the P-51 is off the runway.
http://www.youtube.com/watch?v=i5HfqMtksBI&feature=share
LOL. That was our birds at Thermal this year.
And yes, there are MANY reasons why the F8F got off and away logn before the mustang.
1. Most the hard numbers have been covered already. One that has been more overlooked than other though, take into consideration fuel capacities (wet weight, even though the P-51 in the clip does not have it's aux tank anymore (trust me)).

2. One is blatantley made for carrier operations, the other for 2,000 foot runway conditions.
3. This is more of a 1 + 2 from above thing: the F8F sits twice as high off the ground, and has a propeller of almost equal-sized air-beating proportions. At this particular runway that this filming took place, it is called the "thermal airshow"... some *cough* carrier *cough* planes like taking off in a stiff breeze a lot better than others.
4. I am 80% sure, if I can recall from two months ago, that the two pilots that day were as far opposites as you can get, with different incentives of getting into the air and then back "home".

a. "Mutha" I think is in the F8F. Besides his profession allowing him the leasure of showing up on the museum's tarmac with a $70-million 40-ton 6-month new Super Hornet a month later (he is the Commodore of Lamoore and the entire Pacific Fleet Fighter Wing), i believe this is the show that he got to take the Bearcat back to Lamoore afterwards and showoff around the base for a week (That thing was wheeles up before you can say "Iz cans borrows toy for week and takez tos F-18 fighter training baze!?").
b. The other pilot in the P-51 is a very nice and gentle fellow pushing I'd guess 70-years. You couldn't ask for a better pilot to make sure nothing gets rushed doing it right and to treat the one of those two planes which was only recently leased to our museum, lol (besides, the pony is the favorite of the two).
PS - That IS the same F8F that emergency glided/landed at Burbank Airport (now Bob Hope I think) a few years ago. Also I heard a rumor that one of our Yak3s finally flew again this past weekend.