kegger, try putting all those lines on the chart together, instead of fleeting it with the eye and making quick assumptions - the eye can be deceptive.
1. The P-51B, starts outclimbing the P-51D above 10k, with the maximum gap between the climb rates more than 500fpm at 15k. This difference closes down momentarily at 20k, but starts to open up again above 20k, where the P-51B again, starts to gain better climb rates.
2. The P-51D, is 5~7mph faster than the P-51B, from sea level to roughly 12k.
Between 12k to 20k, the P-51B is faster by about 10~12mph max.
Between 20k to 27k, the P-51D is again, faster by about 5~7mph, with the largest gap at 22k, with about 10mph speed advantage.
Over 27k, the P-51B is faster.
..
If we had the G6 vs the B model pony we would be some what at a close alt, thus the fight would be more evenly matched.
"Evenly matched" ?
You're using the fact that the P-51B being slower 7~10mph max in a limited 7,000feet altitude span is a reason to put in the P-51D.
And yet, you take a plane which is slower than the P-51B, by a considerable margin at all altitudes, which is slower than the P-51B by 20mph even when it is at its fastest altitude, and call that an 'even match'?
How in the world can you state that a fight between the Bf109G-6 and the P-51B, is "evenly matched"? The P-51B is faster at all altitudes. The P-51B climbs simular to the G-6 from 12k on, and starts outclimbing it over 22k. The G-6 for heaven's sake, can't even break the 400mph barrier in level flight.
Sheesh, your definition of "evenly matched" is severely twisted, m8.