Larry Hamm wrote:
>I would advise against much taller tires with a stock diesel Westy,
as you may wind up losing top speed, and will have less power
at all speeds."

I've talked to several 5-speed atmo 1.6 diesel Vanagon or Westy
owners, and every one reports a higher top speed.  I think the
top end toque drop is limiting the vehicle speed rather than peak
horsepower, so I think that tweaking to a slightly taller effective
gearing will work if the diesel is running well.
Just my opinion.
John.