Here is a picture of the ProFlo that I had for a while. (sold it on Moparts to a member)

I don't have a ruler in the picture but you can kind of figure out how tall it is by looking at the other parts on the engine. I think the Pro Flo is roughly the same height as a Victor intake plus a carb. So you are saving a couple of inches that the air cleaner usually takes up.

The hassle is the throttle body clearance around the thermostat housing and upper radiator hose and all of that stuff. I'm sure people have figured it out but I haven't seen a lot of pictures posted. There is at least one Moparts member who has a Pro Flo in his E body. I remember seeing pictures of it before and it looked really clean.

The good news is if you go CNP you can ditch the distributor and use one of my cam sync units. That eliminates a bunch of interference issues with the throttle body and the distributor and cleans up the front of the engine.