These BBK Performance shorty tuned Length exhaust Headers are designed and constructed as direct fit replacements for all 99-04 GM Truck and SUV 4.8L and 5.3L applications. Each header is manufactured with 1-5/8 CNC mandrel bent tubing that offers unrestricted exhaust flow for increased horsepower and torque over factory OEM manifolds.BBK tuned Length headers offer improved scavenging waves for better combustion, which leads to improved performance and fuel economy over stock or equal Length headers. As with all BBK Performance exhaust headers they feature a 3/8 laser cut flange for additional strength and a guaranteed leak free fit. All headers are robotically and precision hand welded and then pressure tested to ensure years of reliability and performance in the real world. All BBK exhaust headers are available in a Titanium Ceramic or polished silver ceramic coated finish and include new exhaust header gaskets, header bolts and hardware to complete the installation. Direct Bolt On - All Gaskets Hardware Included - Direct Bolt On - 50 State Legal. BBK 99-04 GM Truck SUV 4.8 5.3 Shorty Tuned Length Exhaust Headers - 1-3/4 Titanium Ceramic. Processing begins as soon as an order has been placed, therefore we cannot change, cancel or modify orders once they have been confirmed. Most e-mails are answered within 24 hours, including weekends and holidays.