Well the record was prolly done at low altitudes where its very likely that the Bf209 was faster than anything until that 3000hp Bearcat. Look at the speeds that the best unlimited P51s post at Reno they all top out in the 450-460mph range and thats with highly modified airframes, babied tuned engines, no weapons, no armor, no weapons pylons, glossy paint and all - but they hit those speeds down low. Now compare that to the full combat ready P51H which posted a top speed of almost 490mph but at 25k at lower alts its in the low 400mph range.
