One of the areas where new cars do well is the gearing. The lower/deeper transmission ratio gets the car moving quicker while the overdrives allow lower rpm cruising at speed. The new cars don't need deep axle gearing to get moving from the line. Our 2015 Challenger R/T had a 3.07 diff. The 8 speed auto has a 1st gear ratio of 4.7 to 1. Final drove through the OD 8th gear is just over 2 to 1. I'm guessing that the Viper has similar gearing.
I would LOVE to use an 8 speed in my car along with a 3.23 gear. I used to run a 3.91 with the Gear Vendors OD. I now run a 3.55 in the car since I sold the GV. The 3.91s and 4.10s gave snappy response though.
