Fits 1968-1972 GM A-Body, 3.00 inch Aluminized Steel -. This Crossmember-Back American Thunder system is custom designed for high horsepower and large cubic inch engines in 1968-1972 GM A-Bodies with a V8 engine. It's a true-dual exhaust system featuring all mandrel-bent 3.00-inch aluminized steel tubing with a built-in H-pipe crossover assembly flowing into a pair of large cased Super 40 Series performance mufflers for maximum power and a deep powerful aggressive exhaust note. The large 3.00-inch mandrel-bent tailpipes are custom bent to tuck up high above the rear end and exit with a slight turn down under the rear bumper. The system is constructed from aluminized steel and includes all necessary hardware and hangers for installation and is covered by our 3-year Limited Warranty. This system is also available in Stainless steel and comes with a Lifetime Limited Warranty, check out part# 817200.. Systems do not include header reducer cones or downpipes to connect to factory manifolds.