Part Number: 319900 1998 Lincoln Navigator Gibson Exhaust System Swept Side Polished 1998-1998: Base; 8Cyl 5.4L; $397.64 Gibson Swept Side Exhaust Systems Part Number: 319991 1999-2002 Lincoln Navigator Gibson Exhaust System Swept Side Polished 1999-2002: Base; 8Cyl 5.4L; $397.64 Gibson Swept Side Exhaust Systems Intermediate pipe is 2.500 inch x 3.000 inch diameter. Part Number: 319999 2003-2006 Lincoln Navigator Gibson Exhaust System Swept Side Polished 2003-2005: Base; 8Cyl 5.4L; 2006-2006: Luxury; 8Cyl 5.4L; 2006-2006: Ultimate; 8Cyl 5.4L; $397.64 Gibson Swept Side Exhaust Systems Part Number: 619999 2003-2006 Lincoln Navigator Gibson Exhaust System Swept Side Polished 2003-2005: Base; 8Cyl 5.4L; 2006-2006: Luxury; 8Cyl 5.4L; 2006-2006: Ultimate; 8Cyl 5.4L; $546.81 Gibson Swept Side Exhaust Systems Part Number: 69600 1999-2002 Lincoln Navigator Gibson Exhaust System Dual Sport Polished 1999-2002: Base; 8Cyl 5.4L; $624.01 Gibson Dual Sport Truck Exhaust Systems Intermediate pipe is 2.500 inch x 3.000 inch diameter. Part Number: 9400 1998 Lincoln Navigator Gibson Exhaust System Dual Sport Polished 1998-1998: Base; 8Cyl 5.4L; $478.50 Gibson Dual Sport Truck Exhaust Systems Intermediate pipe is 2.500 inch x 3.000 inch diameter. Part Number: 9522 1999-2002 Lincoln Navigator Gibson Exhaust System Polished 1999-2002: Base; 8Cyl 5.4L; $478.50 Gibson Dual Extreme Split Side Exhaust Systems Part Number: 9600 1999-2002 Lincoln Navigator Gibson Exhaust System Dual Sport Polished 1999-2002: Base; 8Cyl 5.4L; $478.50 Gibson Dual Sport Truck Exhaust Systems Intermediate pipe is 2.500 inch x 3.000 inch diameter.