For what it's worth, my Blasty is quite capable of beating 400's. I proved it at Busco, much to my own surprise!

I have a KOR ported/polished/head modded engine, but all my engine work is in the top end only. The whole bottom end is stock. I'm running a Trinity pipe and 34mm carb.
As long as you get a good launch, you can get a 400 almost all the time with a good port/head job and the supporting mods. I took down a stock 660 Raptor, too, so assuming a 440ex runs about the same as a Rappy 660 you should be able to pull it off.