Why arenít bigger throttle bodies a good idea on a stock Viper?
You will pick up some top-end power with larger throttle bodies, but you will have to trade off some low-RPM torque to do so. The stock setup is optimized to keep the airflow balanced for the stock setup. Which means that a larger-bore TB will slow down the airflow into the motor, at low RPMs. And realistically, donít expect to gain more than 5 to 10 hp top end.
One person commented: "I had the stock TBs enlarged to 61.5mm and I wish I would have left them alone. Since I enjoy the low end torque, I was really disappointed. However, I made up for the difference after installing Crower <roller> rocker <arms>."