I have to add some information to the previous post.
The hole on the front of the adapterplate has a connection to a small hole near one of the two primairies. But I dont know what it is for?
here a picture with some arrows of my adapter:
this is a clearer picture of the hole in the adapter
I got a picture of the web of a quadrajet baseplate and my hole seems to line up with some hole in the baseplate. it seems to line up with the hole near my arrow...what is that for?