OER Parts offers a wide selection of Cooling System Components for your 1973 GMC C35/C3500 Pickup. OER Parts offers 1973 GMC C35/C3500 Pickup Water Pump Pulleys, 1973 GMC C35/C3500 Pickup Single Groove Water Pump Pulley, 1973 GMC C35/C3500 Pickup Double Groove Water Pump Pulley, 1973 GMC C35/C3500 Pickup Reproduction Water Pump Pulley, 1973 GMC C35/C3500 Pickup Chrome Water Pump Pulley, and 1973 GMC C35/C3500 Pickup Machined Aluminum Water Pump Pulley.