The vapor valve is just pushed into a rubber bushing. It's typically very dry-rotted and very difficult to remove. I found that soaking it in some PB Blaster for a good 30 minutes let me pry it out without wrecking it.
This isn't the most active II forum, but there are a few good guys here who know their stuff.
The most active community by far is Mustangii.net, those guys live for these cars.