Respectfully request what to look for when shopping for a used carb

Edelbrock carbs=garbage!!!..much better carbs out there to buy!!
Sorry; gotta disagree. I have had big problems with a few Holleys, and have had amazing good luck with Eddys. My modified 340 runs like a top with the 650 Thunder series and will roast the tires.

That's a lot to pay for a used carburetor when you could put half again with it and buy new. DO it smart.
I totally agree. New ones are not all the expensive. Plus think about this. If you are going to use it to test and tune engines, I would want to start with a known good carb.