Say it what it is. The "BAD BOYS" of today are "Keith Black" Hemi motors, perfecting the Mopar ones. I'm far from an expert on this, but I would bet, they are not 426's. 10,000 HP is a lot of ponies.
500 cubic inches. Sure, they are all aftermarket blocks and parts, but they are based off the classic 426. Calling them anything but a Hemi doesn't make much sense.