I have a 1" open spacer on my Edelbrock EGR. The spacer is needed for the EGR clearance on the manifold.. I built my engine for low end torque, and the open space made the engine hard to tune.
I am now going with a 2" Edelbrock spacer, with four ports. The open spacer is great for mid range, but for the bottom, the four port spacer is what is needed.