Your ignition timing needs to be adjusted.
Backfiring in any motor is either badly out of time or a burnt valve.
yes, backfiring is always due to ignition or timing problems. Backfiring through the carb can be a symptom of a lean condition.
Backfiring through the carburetor and no power would seem to be symptoms indicating a problem with your timing. Have the distributor checked.
the choke is not working properly
depends...does it have a carburetor or fuel injected..?
I would check and make sure that isn't just water. Condensation occurs on the inside of the tailpipe as the vehicle warms up... If you had gasoline coming into your tailpipe you would experience backfiring, extreme backfiring.
Backfiring is a timing issue.
The year, make and model info would be helpful but a large vacuum leak could do that.
if you have a carborator, it may have to be adjusted
I would suspect it is not timed correctly.
you would adjust it by re-jetting the carborator
My Preference would be a 600 Edlebrock, but for those who like Holly's a 650 with vacuum secondaries would be good too. -Josh