Hey lq1969 and cliff,
First off, thank you both for the helpful responses. Definitely appreciate the editing of the picture so I can see what you mean.
My only experience with carburetors so far has been the Q-jet, so I thought I would play it safe and ask before installing and setting this one up.
Now, as you guys have mentioned, port "A" can be used for PCV or brake booster, provided there is no port on the intake manifold for the brake booster. I will check to see if the intake manifold has a port for the booster.
Port "B" is an air inlet for what I assume would have been the hot air choke? Since the electric choke conversion has been done, I might as well leave it plugged up.
Port "C", the small inlet is for the Ford -style vacuum advance, but I assume is fine to use on a GM HEI?
Again, thanks for the help!