Flowmaster is proud to introduce our American Thunder dual exhaust system for 1967-1974 Camaro and Firebird, and 1968-1974 Nova. The system features our exclusive 80 Series Crossflow performance muffler that tucks up high behind the rear differential. Other features include all mandrel-bent dual 2.50 in. head pipes with a built-in H-pipe crossover and dual 2.50 in. tailpipes for a deep rich sound and optimum performance. This header-back aluminized steel exhaust system gives these classic muscle cars a moderate tone inside and out. The system includes all parts, hardware and illustrated instructions and is covered by our 3-year Limited Warranty. If you prefer Stainless steel construction, check out optional system# 817104 which comes with a Lifetime Limited Warranty. Notes: Does not include header reducer cones. Convertible models will require adding 3/8 in. of shims to the stock factory X-brace for clearance or purchasing Hotchkis Performance Convertible brace Part# 1404.