Domon isn't making singles, or at least not yet. They are making 2 bbls loosely based on the Stromberg 97/Holley 94 though.
I will throw another option for you, though. The Holley Model 1904. It's mainly a Ford/International carb, but I have seen them on GMCs, too. If you use the Ford/International version (or V6 GMC), the throttle arm will be on the wrong side, but can be modified to work wit a Chevy intake. Re-jetting is easy, too, as the jets are the same as a modern Holley 2 or 4 bbl.
