There is a German version of the wasserboxer with
 something like 115 hp, high compression engine.
Those vanagons can go 160 km per hour (or 100 mph).
Didn't have a catalytic convertor, and uses high octane gas.
When I go long distance in our '90 westy, like for days on end,
I usually cruise at 65 mph (3800 rpm) for engine longevity.
Sometimes on short stretches, it easily goes up close to 90 mph,
 but then the rpm are out of the ribbled green zone.
I don't keep it there for more 10 minutes.
70 mph is 4,000 rpm, right on the edge of the solid green.
That's already a lot of revving, especially for days on end.
Like when you're on a 5,000 mile trip.
75 mph, maybe for half an hour or so, but not long distance.
Harald
'90 westy with wasserboxer auto tranny
ceramic coated heads and new Mahle pistons
http://www.geocities.com/harald_nancy/index.htm