demon carburetor information

This won't help you now, but since Holley bought Demon they have started stamping part numbers on all Demon carbs. I know on the Mighty Demons they is a number stamped on the main body. 37=650, 40=750, 42=825. That's off the top of my head. If there is no dimple then it is a RACE Demon and has removable emulsion bleeds. But yours looks like a Speed Demon to me.