Try a pre-'50 Chevy or a GMC.
I've got a bunch of Holley 94's (two barrel three-bolt flattie carb) that I am going to use on a multi-carb setup that I haven't tuned yet, but you can get adjustable jets and various power valves for them to make them easy to tune, and they never leak. Downside is that they are expen$ive.