I,m new to the forum. I have a 1978 F250 supercab 4x4, with a V8
400. I ordered a build sheet from Ford and am returning everything on the truck to its stock original condition. The build sheet states the truck has a heater on the block, which was part of the Northland package. I can't find any heater wire plugs anywhere. I have looked at other trucks and found an electrical plug hanging from the front grill and assume this is part of the block heater. I have also found a truck with a plug wire and heater unit spliced into the heater hoses that go to the heater core, I assume this helps heat up the radiator fluid and warm the truck up sooner or open the thermostat sooner. What type did Ford use as original oem equpment ? The type with the cord showing from the front grill, what does it connect to and where on the motor is it attached ?

 

I believe most factory block heaters are special 'freeze plugs' although I'm not positive about what FoMoCo did in the 70's. Basically it's a freeze plug with a 'U' shaped heating unit and a cord that runs to the front of the engine compartment. One of the factory freeze plugs is removed and replaced with the block heater.