Carb replacement options???

73 Dart slant six automatic..I need to replace the Carb.

Which is the most reliable vendor and what exact carb will get me the most mileage and run smooth too?
The engine is a re-man with only about 10K on it and I want it to run like it should. I have gone thru the Holley with only minimal success. The car runs RICH no mater what I do. Runs rough at idle and is hard starting (cold natured). Floats were adjusted several times..no intake leaks or other issues.
To sum up...:prayer:I give up on this dern Carb!

I put the electric choke kit on it and it helped a lil bit. I am convinced it is the Carb and I am not smart enough to cure it.

I looked at all the Carb sites and they ALL swear they are the best..bull pucky. I am sure someone has tried and found a good one.:banghead:

There are two for a later model Dart on ebay..will they interchange?