CIS question

[Wolfsbrg8v at aol.com (Wolfsbrg8v@aol.com)]

I noticed that on my control pressure regulator, 
besides the two fuel lines attached, there is a 
vacuum port which has been capped.  From what 
I understand, some CPRs enriched the mixture 
in response to manifold vacuum, and I'd like to 
experiment with this. 

My question is, where do I run a vacuum line from,
to attach to this port?  I'm thinking from the same
line that runs from throttle body to distributor, or
maybe from the intake manifold .. ?

Leo
late 84 8v