I cobbled up a fan out of a 69 bug gas heater, (has a nice compact tubular
fan), and stuck into a modified air dist tube, (the one that runs
vertically and has the side branches for foot heat and the lever for
defrost), on my '72 westy. It did indeed boost the flow, but the noise was
intrusive. A better location is under the front, but I didn't want to
realy start cutting, when it was only a lark. I guess the disadvantage of
an inline fan (apart from the noise) is that you have to have the fan
going a bit to get the same airflow if the fan was not installed. I tried
using a headlight switch/instrument dimmer rheostat as a speed controller,
(remember, this was a lark!), but of course it soon started to smoke.

Alistair