Integration perspective:

It was suggested that retaining the original atmo Vanagon 4-speed manual
transmission in a more powerful repowering installation could  be fairly
described as follows:

"You *can* use the existing transmission just like it is. You will have
incredible acceleration around town, but the egine RPM's are a bit high on the
highway."

Certainly acceleration for the first 100 to 150 feet would be faster by
retaining the diesel specified overall gearing ratio.  But after that, the
average horsepower between shift points will govern average acceleration.
Since the gear staging would be either identical in this comparison, or so
similar as to be of little importance, and the engine's torque curve would be
unaffected by which overall ring and pinion ratio is selected, I think the
statement above overstates the case for the lower overall gearing ratio's
ability to provide "incredible acceleration around town."  The speeds at which
peak horsepower is applied in each transmission is dependent on these ratios,
so we will find speeds for each transmission where it shows an instantaneous
advantage over the other.  But, for average horsepower between shift points,
which I contend is the most meaningful around town acceleration predictor,
neither final ratio has a global advantage over the other after the initial
start.
Agree/disagree?
John