what does an evaparation filter join to on an abf?

[clipperjay]

You mean evaporator?
If there is it might mean the car it was removed from had A/C ? Air con?
Old 8V's used to have a evaporator filter or carbon activated filter to vent excess fuel fumes to atmosphere! 

There you go mate lets explain in detail painfully to something irrelavant and non usable on his MK2!

[DOA]

Lol. Hows about not saying it vents excess fuel in the first place  . Dont worry chap, only having a laugh and he did seem interested in what the system was, maybe someone else can learn something too  .

[clipperjay]

Lol. Hows about not saying it vents excess fuel in the first place  . Dont worry chap, only having a laugh and he did seem interested in what the system was, maybe someone else can learn something too  .

I didn't it was Fuel fumes by the time the charcoal works its vented out everywere breathers back box you name it! 
I'm not worried. But thanks for pointing it out!