This is the alternator setup that you need.
You also need the plastic ducting for the engine compartment and the
ductwork down to your heat exchangers.
If you run the van with out the airflow through the heat exchangers the
aluminum heat sinks inside the exchangers melt off and ruin the heat
exchanger.
You also need the rubber boot to connect the alternator intake to the
fresh air duct, else you breathe dirty air and possibly carbon monoxide
from your exhaust.
I've got some of the parts you need, but I'm not sure what all you're
missing.
http://williamwareagency.com/forsale/stanvan/parts.htm

Stan Wilder
83 Air Cooled Westfalia

On Tue, 12 Feb 2002 21:06:57 -0500 Tim & Kim Dayton <5days@PRODIGY.NET>
writes:
> I recently, 4 days ago, bought an 1882 Westy with a 1978 engine in
> it.  The engine runs well, except for minor push rod tube leaking.
> However the heat is sub-optimal for an air cooled engine.  The heat
> coming from the defrost vents is warm yet not hot.  This engine
> doesn't have the rear blower in front of the alternator like those
> found on the 82 engine.  Could this be the cause of lack luster
> heat?
>