Based on the FLEXJET NHRA Factory Stock Showdown performance numbers from the NHRA Nevada Nationals at the Strip at Las Vegas Motor Speedway in Las Vegas, NV, the NHRA Technical Department is reducing the supercharger overdrive by changing the upper supercharger pulley for the 2019-2023 Chevrolet COPO from 3.375 inches to 3.625 inches, 2019 Ford Cobra Jet from 3.500 inches to 3.750 inches.  The minimum weight will also be reduced by 25 pounds, from 3550 to 3525 on the 2019-2023 Chevrolet COPO.  This rule change 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.