Exhaust Y-Pipe for GMC Yukon (1999-2006)High Flow Exhaust Y Pipe for 1999 2006 GMC Yukon (Vortec V8 GMT800) Replaces the restrictive factory exhaust crossover to optimize scavenging, reduce backpressure, and improve throttle response on Gen III Vortec V8 engines. The Stock GMT800 Exhaust Bottleneck The factory OEM Y pipe on the 1999 2006 GMC Yukon is a recognized flow constraint in the exhaust system. General Motors utilized heavy, crush bent tubing with abrupt junction angles that disrupt