The headers are constructed of 3/4" stainless steel. The "Y" pipe terminates in approximately the same location as the stock 2.8 "Y" pipe, enabling you to use a catalytic converter and a proper muffler for a mellow exhaust tone. This enables you use our 2 1/2" Cat-Back exhaust system to match the flow necessary for your high output 3.4 TDC engine. The "Y" pipe comes shipped with 3-bolt flanges to mate with your existing exhaust manifold and a 2-1/2" 3-bolt flange to mate with a 2-1/2" down pipe. This "Y" pipe is constructed of 2 1/4 16 gauge mandrel bent steel or stainless steel tubing. This "Y" pipe will fit both the early square port and later rectangular port TDC's.