OER Parts offers a wide selection of Emission Control Components for your 1974 GMC C35/C3500 Pickup. OER Parts offers 1974 GMC C35/C3500 Pickup Catalytic Converters, 1974 GMC C35/C3500 Pickup Check Valves, 1974 GMC C35/C3500 Pickup EGR Valves, 1974 GMC C35/C3500 Pickup Emissions Sensors, 1974 GMC C35/C3500 Pickup Hardware, 1974 GMC C35/C3500 Pickup Hoses & Clamps, 1974 GMC C35/C3500 Pickup Mass Air Flow Sensor, 1974 GMC C35/C3500 Pickup Pulleys, 1974 GMC C35/C3500 Pickup Smog Pumps & Components, and 1974 GMC C35/C3500 Pickup Vapor & Charcoal Parts.