392 or 6.1
There are several cams from Comp and others. The comp cams are showing big gains. And as time passes there are sure to be more aftermarket support available.
22 more cubic inches
Better flowing heads
Stoughter block
Variable valve timing (good for more low end torque as well as top end power)
Variable runner intake (good for more low end torque as well as top end power)
What's not to like?