<< Thanks Ken, but after talking to the Bosch tech rep, I am staying away from
 the 4-pronged plug.  Bosch tested the plug in all possible engine
 applications, including the Vanagon, and it did poorly in the Vanagon, which
 is why the parts stores show no listing for it in the Vanagon.  The tech rep
 said to not use them in Vanagons >>

Did they give a reason as to why they did badly?

I am running then in my 73 custom 2L and it lowered my head temps more than
30 degrees with an increase in power.

In my customized 2.1 L Wasserboxer they run better than the single tip or the
triple electrode Bosch plugs, starts immediately when turned over.

Robert