OK, how about this.
Chevy went with a 427ci small block in the Z06 (remember the 427/425 horse big blocks, L88's, ZL1's, etc. of the '60's). Well, Dodge is pretty inclined towards nostalgia too ("Charger", etc.). How about a 500+ hp 426ci Hemi
for the Viper. Lose nose weight (aluminum block and heads), create buzz with the return of the 426ci Hemi (only available in the Viper), get a closer tie to the Cup program with the Hemi being in there, etc., etc.?
I love my V10. This might be a way to differentiate the new car in a positive way, using the hottest property (in the public's eyes) that they have right now (the Hemi).