For 331 354 392 Mopar Hemi Stainless Steel Headers Header Dodge Chrysler Shorty Huge 1 3/4" by 2 1/4" Primary Flanges that open into 1 3/4" Primary Tubes 3" Collector Stainless Big Block Mopar Engine Swap Headers(pair) 4 to 1 Header Design to Create a Compact Package for Universal Applications Professionally Tigged Welds