Jeff & Fred Hurst Chrysler Dragster powered by a 600 cu. in. Indy Cylinder Head engine with 600-13 heads. It is one of the nicest dragster's in the country. Jeff won the Top Dragster race at the JEG's All Star event held in Columbus, OH in September 2007. Jeff has gained approximately .05 with a purchase of a set of Fab Shop Chrysler Dragster Headers. He took a set of 2 1/4” to 2 3/8” x 4 1/2” Headers off and installed a set of Fab Shop 2 1/4” x 4” Headers. .04 Out of the box. We have also tried a set of 2 1/8” to 2 1/4” and saw another .01. Once again proving there is more to consider than just how big around the pipe is.