Dude, there are 426s making 650HP on pump. Just go over to the LXforums and get educated - PLEASE.
That is true, and before someone chimes in and says BFD there are LS7s making 600rw, remember, this is with the stock heads/intake--which were never meant to feed an extra 56CI.
Arrington is making an aftermarket intake and AFR is developing heads. Soon there won't be much difference between a built Hemi/LSx.