(Edit: missed gvw when I wrote this, but it's unusual to typify a vehicles P/W ratio by GVWR. That's more a comment on its structure and suspension.)
Had there been the Oettinger flat-six available in US-market transporters from the beginning, perhaps the minivan market would've turned out a little different....
Wanna know why inline fours bolt up so nicely in Vanagons? Because VW originally intended to put an inline in them. I mean, do you really think VW wanted a an air-cooled engine with friggin' ignition points in a 1980 model? And an anemic, decades-old engine design in a 4000lb. (in the case of our Westfalia) vehicle?
Had VW not done their usual (IMO) half-assed planning and design, it might have been different. But then they wouldn't be VW, would they? :-)
It doesn't mention Westfalia models directly, though, unless they're one of the model numbers in the breakdown.