They are giving crank HP which is definitely within the 426's power range....Rear Wheel HP (RWHP) would be closer to 500 in an auto and ~15% power train loss....
Wow, that seems to be a pretty hefty loss at the wheel. The 392 was 470 and around 420 to the wheel - right?
On a separate note, does anyone really think the "hellcat" will put out more than 550 at the crank? 6.2 liter + s/c (100 hp). That would be what 460-490 or so to the wheel?
590 crank hp is not a big deal with a decent camshaft and ported heads. Quite a bit more is possible depending on how extreme you want your setup to be.