Ld340 intake holes

Ok, my bad. I was distracted by the arrow. I now see the hole in the middle, near the bottom below the carb base. But the photo 4spdragtop posted seems to have a plate, or something, in that area that the OP pic doesn't!

I do recall that there were 2 different LD340's. One had a Chrysler part number cast into it and the other one was Edelbrock-only. Don't know if that makes a difference. But it doesn't explain what the hole is for.