Just to clarify- in my devac writeup above, the "ported vacuum" that I was using to work the EGR refers to manifold vacuum taken at a spot just above where the throttle butterfly closes fully (that's why these ports are at the very base of the carb). This type of vacuum is pretty much like manifold vacuum except it is zero when the throttle is closed (at idle).
You're right, I got my terms backwards there. It's venturi vacuum that's needed!