edelbrock 1406, running way rich, how do i tune them?
All of the above.
What sort of cam do you run?
Are you sure the carb is clean, not all gummed up inside?
Has someone before you (used carb?) been "into" the thing diddling with the metering rods and jets?
You might have "junk" in one or both needles, causing fuel to leak past. Can you hold the throttle at some RPM, and look down the carb throat? Do you hear or see fuel siphoning over into the throat? This makes an erratic popping sound sort of like bacon frying.
Too high fuel pressure
Floats damaged
Floats set too high
Needle/ seats damaged/ dirty
Carb is dirty/ gummed up, metering rods stuck
Carb has been "effed with" by previous owner