ORIGINAL: RLSH700
The fuel consumption would be terrible (unless they finally give it taller gearing and put the Challenger on Jenny Craig).
I'm pretty sure four valves improves fuel economy, and will help with emissions, also. It makes sense.
ORIGINAL: Dutchmaster151
I think that dodge would have trouble putting such a big engine stock in a challenger, as they are already having problems matching a 6.1L hemi to a manual transmission.
They would use the same Tremec as in the Viper, which is good for 600 ft-lbs. If GM is going to 600, why shouldn't Chrysler?