390 double pumper vacuum

He didn't ask if you've ever heard of it or if they exist, I mean, there it is. Still available new from Summit.

To the OP, have you looked closely all around the base plate? There are usually one or two large manifold vacuum ports there, as well as sometimes some smaller ported ports. The primary metering block appears not to have the timed spark vacuum port on the passenger's side for the distributor. It is more of a race bred carburetor, so it may be lacking some of the vacuum control a more street oriented carburetor would have. You're just going to have to look closely and see.