Popping sound in exhaust

[KillerBee1972]

Ok, here is my problem, i have a 340 that in idle will sometimes pop/ backfire through the exhaust. It sounds like it is coming out of the drivers side. I do not have any exhaust leaks. or vaccum leaks that im aware of. I have 69 340 points distributor with new plugs, wires, cap, rotor etc... the plugs look normal not fouled out, and timing is correct, I dont know whats going on other than that i might need electronic ignition  The motor is basically stock only upgrades are intake, carb, and headers. While driving the car runs great a little sputtering when i get into the gas. which might be a problem also. Please if someone had an idea of what might be wrong let me know!! Thanks

Scott

Maybe my carb needs tuned.... I dont know thinking out loud i guess.

[Chryco Psycho]

The most common causes are air leak into the exhaust or timing to far advanced , you say you have no leaks so you are saying you have the timing right .... timing at idle or at RPM ?
Typically I set the total timing which is more important @ 36-38* at say 3000 rpm , [ 2 3/8 inches clockwise on the damper is 36* if you mark it there] & try to get the idle around 14-16* often the engine will run better without vacuum advance connected at all , this will shorten the timing curve & get you closer to the spec you need to be at .
Let us know what happens if you reset the timing this way

[KillerBee1972]

I set the timing a zero, thats what my 72 dodge book says, and thats at idle, and if you would rev the motor and let off, then you will hear a popping noise, and now you can hear it more at idle, i was told from some of my mopar buds that it sounds like a air leak pop but for the life of me can not find a leak. I will try what you described tomorrow, would any of this be possibly caused by using points still?

[Charger 512]

Check your spark plugs or u might have a burnt valve.

[myk]

Personally I wouldn't go by what the book tells you.  I've learned that tuning by ear is the best way to go.  These cars left the factory a long time ago...

[Budnicks]

Probably already said... Exhaust leak in pipe or manifold/head pipe flanges, bad or burnt points &/or wrong dwell etc., burnt or bent exhaust valve, lifter sticking or bad all together, bent or worn out push rod, worn rockers &/or shafts, loose plug, carb problem...  Just spit-balling here it maybe none of them

[Chryco Psycho]

if the points are set properly the points will not be the problem .