1991 GMC C3500 | Sierra, Sierra SL, Sierra SLE, Sierra SLT, Sierra SLX | 8 Cyl 5.7 L CNG, 8 Cyl 5.7 L GAS, 8 Cyl 6.2 L DIESEL, 8 Cyl 6.5 L DIESEL, 8 Cyl 7.4 L GAS
1991 GMC C3500 | Base, High Sierra, Sierra, Sierra Classic, Sierra SLE, Sierra SLX | 6 Cyl 4.8 L GAS, 8 Cyl 5.0 L GAS, 8 Cyl 5.7 L GAS, 8 Cyl 6.2 L DIESEL, 8 Cyl 7.4 L GAS