There were early Rochester 4G carbs before the later 4M carbs (Q- Jets) that are mostly seen around today. The 4Gs were used on 275hp 327 engines up to around '68. They flowed less than the 4Ms that are 750 cfm or so.
I would think that just about any carb with a vacuum secondary system would work. If you can find a good Q-Jet, it would work for your engine. They just have too many moving parts for my small brain.