1981 GMC C6000 Engine: 10.4L V8 DIESEL; Position: Heater Outlet;. 1982 GMC C6000 Engine: 10.4L V8 DIESEL; Position: Heater Outlet;. 1983 GMC C6000 Engine: 10.4L V8 DIESEL; Position: Heater Outlet;. 1984 GMC C6000 Engine: 10.4L V8 DIESEL; Position: Heater Outlet;.
