My 1981 E350 7.5 has two small tubes going from the carb to the manifold and they are rusted through. Can these be replaced? What are they called? Are they vacuum lines? The guy at the parts place couldn’t help, said they probably are no longer used, maybe made from something other than metal nowadays.
It may be part of a “heat riser” mechanism, which helped the carburetor know when the engine was warm. If it is and you care about fuel mileage, then it’s worth fixing. It may be a dealer-only item at this point.