Try here
http://www.network54.com/Forum/88781/Best forum on the planet for Autolite carbs.
Somebody may have swapped a booster on that carb, that changes all the air bleed sizes. Common problem if carb has been played with.
Or it could be dirt, etc.
You know, those will run with the lid off so you can check the float level wet. Do it outside though & if youre new to them have a fire bottle handy. I've never had a problem in 40 years, but just in case.
Lid comes off w 4 screws and the aircleaner stud. Then set the lid back on, start it, and take the lid off. You can see the float level, should be about 3/4-13/16 below the top surface.
While the lid is off, you can pull the booster with that one big screw. Don't let any parts drop down (or just pull the carb). CLean the booster in carb cleaner or lacquer thinner, acetone, etc and blow with air a couple times, make sure no holes are plugged.
On the left front mounting foot there should be a number like c6df-a or just 6d-a, that identifies the carb.
On the bottom of the booster there will be a letter stamping.
The carb forum folks will want that info. They are good folks over there.
I've run numerous 4100s (the 4bbl version of the 2100) on the Chevy 6, stock jetting is usually right on if the carb is running right.
