Part Notes: Silverado, Sierra; 6.0l; 8 Box; W/O Extended Cab; W/O Rear Exit Exhaust; All; 1 Ton; Standard Cab; Option 1; W/O 9, 900 Gvwr; 4WD; California, Emis. Code Nc1, Emis. Code Nc8;Silverado, Sierra; 6.0l; 8 Box; W/O Extended Cab; W/O Rear Exit Exhaust; All; 1 Ton; Standard Cab; Option 1; W/O 9, 900 Gvwr; 4WD; Federal;Silverado, Sierra; 6.0l; 8 Box; W/O Extended Cab; W/O Rear Exit Exhaust; All; 1 Ton; Standard Cab; Option 3;Silverado, Sierra; 8.1l; 8 Box; W/O Extended Cab; All; 1 Ton; 133" Wheelbase; Option 1; W/O 9, 900 Gvwr; 4WD; W/O Srw; California, Emis. Code Nc1, Emis. Code Nc8;Silverado, Sierra; 8.1l; 8 Box; W/O Extended Cab; All; 1 Ton; 133" Wheelbase; Option 1; W/O 9, 900 Gvwr; 4WD; W/O Srw; Federal;Silverado, Sierra; 8.1l; 8 Box; W/O Extended Cab; All; 1 Ton; 133" Wheelbase; Option 3