Remember, that 388mph is with bomb racks, the clean speed is well known to be around 395 or so!
The 410 has a bomb bay. Is it sure it carries external bomb racks?
WMaker posted a chart on the 1st page, that shows, the 410 had a top speed of 320mph on the deck and 600kmph ~ 368mph at altitude, at 1.3 ata.
Following this logic, if cleaned out, 1.4 ata, it had a top speed of 395 at alt, then it should have (transferring the difference, 27mph), 320+27 = 347mph on the deck? Are you sure?
Still, if it could do 388 at alt, then on the deck it should do 338, whats fairly good, just between the g6 and the g2, close to the p38J/L and the D-jugs. According to the same chart, it could do 565+20=585kmph at 6k, whats like 357mph. Fairly decent.
One more thing.
Look the chart of the 109s, on the same picture
In the characteristics, that curve isnt even simmilar to out 109s.