Whats really interesting is watching these planes, in game, fly at and/or near these speeds with their gear down 
Actually, in the game, these planes don't fly that fast (or even nearly that fast) with their gear down

They can however, lower their gear as a dive brake, which is probably what you're seeing. The F4U gear was designed (in RL) to be used as a speed brake. Lowering the gear in AH is used as a means to slow down, which is how they were intended to be used...
Some people also lower their gear in AH in a miss-informed attempt to turn better. Those folks will quickly find that while the gear does help them slow down (as it was intended) it doesn't help them turn (it wasn't intended to be used that way), and it quickly takes them to a speed below optimal turning speed (working as it was designed), which gets them into all sorts of trouble, and generally killed (because they aren't using the gear/speed brake as intended).