1968 Plymouth Belvedere station wagon. Slant six 225; Automatic; 3:23 axle ration; manual steering; manual brakes; radio delete; vinyl seats. I was 16.5 years old in the summer of '77.
If it is backfiring out the carb it is most likely carb related. Most backfires out the exhaust are ignition related. Try 1 oz. of Seafoam per gallon of gas in the tank. Let us know what the fix is...
I believe this has a lot less to do with pollution than it has to do with government control. Right now it is impossible to lock people down and keep them essentially imprisoned in their homes. They found this out with the recent scamdenic. If all the major population centers (cities) were 100%...