Gary,
You are most correct referring to the sacrificial zinc annode used on
ships and boats, to prevent the electrolysis of the different metals,
between a spinning propeller and the hull of the vessel.

But the spinning prop generates the electrolysis, not the fact that the
metals are different alone.

Now, where is the zinc anode to be placed on a Vanagon, or any their
vehicle?

What generates the electrolysis on your van?

The spinning of your tires?
The crankshaft?
The flywheel?
The speedometer ?

Give me a hint me where this electrical, anti-corrosive gizmo is used by
the government, and on,or in what, and I would like to go see, the end
results of it's use.

What has to be used on a Vanagon to prevent rust is a pair of black
rubber ground straps, with lighting bolts painted on them, to ground out
the negative ions, setting up a positive electrolysis shield around you,
and your vehicle as you drive.
Prevent's cavities,  wards off arthritis, and rheumatism, promotes hair
growth, firms up your ab's, prootes breast enlargement, whiten's your
teeth, as well as warding off the rust.

All brought to you live from the Flim Flam Man Products Inc.

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Terry--
74 Campmobile- (Clementine)
85 GL- (Delilah)
86 BMW 325 ES- (Eva)