It's a fundamentally better design than the 1920 in a fair number of ways. It has some drawbacks that are rather easily corrected; brass floats are available for it, for example.
the 1945 if you can get an early one with relatively little in the way of smog features
Mmm...I don't quite agree here. The first couple years of 1945 (1974-5) tend to be more problematic than the '76-'77-'78-'79 items. About the only "smog feature" that you would need to even think about would be the idle enrichment valve, which was used to allow a leaner/faster-off choke. This valve can simply be capped off and ignored on a vehicle not equipped to control it.
the Holley 1920. Those things are a fire just waiting to happen.
