Based on the FLEXJET NHRA Factory Stock Showdown performance numbers from the first 2 races of the 2023 season, the NHRA Technical Department is reducing the supercharger overdrive by changing the upper supercharger pulley for the 2019-2020, 2022-2023 Chevrolet COPO 350 from 3.125 inches to 3.250 inches. And the 2021 Dodge Drag Pak from 3.375 inches to 3.500 inches. These rule changes will go into effect immediately. NHRA reserves the right in the future to make additional rule changes to control performance and maintain parity in the category.