Several things can cause this. Low fuel pressure due to faulty pump or filter or injectors, inaccurate ignition timing, wrong spark plug routing, intake valve not fully closing, excessive carbon on the intake valve, sometimes it can even be as simple as bad sensor.
Those are general causes.
Corvetteforum.com is a good resource to discuss with fellow enthusiasts.
A leaking spark plug wire can cause a backfire out of the intake, but the most common cause is a burned intake valve. A burnt intake valve will allow leakage during the compression stroke back through the intake causing a popping backfire out of the intake manifold.
Worn camshaft, bent pushrod, burned intake valve, incorrect firing order,
A backfire is caused by many different things. Using the wrong grade fuel will cause a backfire, as the engine's compression ratio is usually too high and will detonate the Air/Fuel mixture, causing a backfire. It can also be caused by advanced or retarded timing. Advanced timing will cause a backfire through the intake, as the spark occurs too early and ignites the Air/Fuel mixture before the intake valve is closed. Retarded timing causes a backfire through the exhaust as the spark occurs after the exhaust valve has opened. Your problem seems to be advanced timing. A backfire is caused by many different things. Using the wrong grade fuel will cause a backfire, as the engine's compression ratio is usually too high and will detonate the Air/Fuel mixture, causing a backfire. It can also be caused by advanced or retarded timing. Advanced timing will cause a backfire through the intake, as the spark occurs too early and ignites the Air/Fuel mixture before the intake valve is closed. Retarded timing causes a backfire through the exhaust as the spark occurs after the exhaust valve has opened. Your problem seems to be advanced timing.
Out of time, or spark plug wires installed on wrong plug.
yes, backfiring is always due to ignition or timing problems. Backfiring through the carb can be a symptom of a lean condition.
Before I can answer your question I need to know if the engine backfires during any other operations, such as putting the car in drive?
Yes, and it will cause loss of power. Better replace the defective parts immediately before you burn your valves and ruin the engine.
No, backfire is usually caused by park plug wires that are installed incorrectly or an engine that is out of time. Fuel filter and pump will not cause backfire.
Incorrect Timing Can Cause Backfire.
Several things could cause this problem. It could be the timing is set incorrectly, the catalytic converter is plugged, the spark plugs are misfiring, or a burned valve.
Having no catalytic converter installed is illegal and can cause a myriad of problems. Probably not a backfire though.
Yes...all valves bent...smacked piston...good old interference engines. Started cranking really fast cause valves stuck open from overheat then...BAM...backfire out intake after only 15seconds of cranking...Head back off again. answering own question. Impossible to say. You need to find out why it backfired. Suggest you do a compression test.