Here are two pictures of the air dam. Just to clarify the engine temperature that I was referring to was NOT the internal operating temperature of the engine but the exterior ambient temperature of the engine.
By lowering the ambient engine temperature it not only makes the cab cooler while running and immediately after shutting the engine off you lower the risk of exhaust manifold issues and will extend the life of such items as spark plug wires.
If your RV does not have high engine ambient temperature great but for those of you that do this does work.
Side note for overheating operating temperature for 1971 -1991 Ford E-350's it might not be overheating it could be a Instrument Cluster Voltage Regulator failing and causing your gauge to show hot.
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