Sean, 
I had the exact same problem with my Westy ('72). 
Remove the panel that hides the gas tank in the engine compartment. There is a
small hose (about 3/4-1" diameter) attached to the top of the gas tank (some
kind of return hose or something). Mine was wasted, and everytime I filled up
the gas smell was so strong we could hardly stand it. When the tamk was not so
full, the problem wasn't so obnoxious. Be sure to replace the hose with neoprene
fuel hose so you won't have to be back in there in a year or two. It's kind of
hard to find that big, so scout around and find a store that stocks all sizes
before you dismantle everything. I wish I could remember the exact size, it's
been about four years.
Good Luck!
Andy McKinley
75112.2101@compuserve.com
'72 Westy, looking for a Thing to buy

"...the car itself was still full of bugs." -Heinz Nordhoff, 1948, rebuilding
the VW after the war.

>When I have a full tank of gas, I can smell the gas inside the car.