1 7/8" Primaries, 3" Merge Collectors, Includes Stainless Steel Mufflers And Polished Stainless Steel Tips (With Cats)1999-2004 Ford Lightning Enthusiasts, if you ve been waiting for big tube headers to handle the brute power you re producing, American Racing Headers has answered the call. 100% U.S. made using the finest 304 S/S, the ARH Lightning system is available as a direct bolt-in to your existing cat-back or as a full 3 system with X-pipe, custom mufflers and polished S/S tips. Primary sizes are 1-3/4 (for street/strip) or 1-7/8 (for high boost race applications). Both come with 3 merge collectors, 3/8 thick flanges with hand ported inlets, provide an easy install and great fit. The system is available with 200 cell metallic substrate cats or off road. With superior quality and unmatched capability, these systems were developed to be the last system your Lightning will ever need. Contact us today and we ll discuss which set-up is best for you.