So you have a 4972 TQ for a 71 340 manual transmission. That is worth only $500-1,000. That is what I ran on my favorite 273, it would be the last I'd ever sell. The 6139 TQ is a 1972 340 automatic transmission carb, I've run this one also on a number of small blocks, one of the best. The 6322 is a 1973 440 Automatic transmission carb rated about 850 cfm, very nice carb and sounds like untouched, the best condition. What a great bunch of choices. I run brass floats, I guess because of rebuilding Quadra-Jets. They would always soak up fuel. Never had a problem with brass floats.
