Backfire thru exhaust not carbs

What's does it typically mean when you get backfiring/popping through the exhaust and not the carbs. At 4500 rpm and up my 308 is now popping/backfiring through the exhaust. It sounds like lighting a pack of firecrackers from 4500 rpm up.
I changed the coil wire on my car to try to remedy my problem that starts at @4400 rpm. At this point the car would no longet accelerate and start backfiring. After replacing the coil wire, I can now accelerate all the way to redline, but I still am getting the firecrackers at the 4500 and above point in all gears.

Ignition comes to mind. I have seen that behavior on my 240Z with a cracked distributor cap. It would run fine until I got into the ignition advance. Contacts inside the cap could be carboned up as well.

Hard to tell without the "process of elimination". Start with the basics. Visually inspect ignition components for arcing/burn spots, carbon deposits and cracks on the distributor caps, rotors, spark plug wires and plug extenders.

Check the set up; static timing, timing with a strobe (if it applies), test for ignition advance, test plug wires for continuity/ resistance,

or

hook it up to a diagnostic scope right off the bat. It may help you zero in on the trouble area a little quicker.

It's hard to tell without some hands on.

DJ