It's about the views.It would be an easy enough test.
Just add a nice bead of clay around the hole on the manifold you’re testing.
It’ll either pick up flow or it won’t.
On the rare occasion I bother testing an intake, which have all been 4bbl units, I found that just mounting a large carb body to the intake was a lot quicker than messing with the clay.
Besides......... it has something bolted on there when it’s running.