Dual Quad 318... I used a 273 intake

I'm considering using a D 64 on my newest 340 build. Is there a reason that you chose not to runs the carbs progressively?
2 reasons:
  1. This intake has a wall between the banks, so it's a long way from cyl #1 to #7 or #2 to #8.
  2. It was just simply easier for me to hook up direct with the pieces I had to work with.....
Does that intake have a completely open plenum underneath both carburetors?...