Not sure what the square openings are. They did produce a lot of noise on his flow test.
Think he was trying open up access to the restricted plenum. Duplicating what mopar did with this 318 dual plane intake withe factory dropped devider.
Will keep watching and see if I can learn anything new. Charles is planning on building a 3" tall "Hour Glass" adapter to go on top of square opening plenum of the manifold.