Based on the FLEXJET NHRA Factory Stock Showdown performance numbers from the Gerber Collision and Glass Route 66 NHRA Nationals at Route 66 Raceway in Chicago, IL, the NHRA Technical Department is increasing the supercharger overdrive by changing the upper supercharger pulley for the 2019 Ford Cobra Jet 327 from 3.750 inches to 3.625 inches for the aluminum block; 3.875 inches to 3.750 inch for the iron block. 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.