1979 Dodge Other

Engine problem
1979 Other Dodge Models V8 Two Wheel Drive Automatic 132000 miles

I'm running out of options for this Aspen. I have been having backfire issues. I have changed the plugs, wires, distributor cap, cleaned the egr valve, adjusted the carb (which is a 2 barrel holley), and replaced the fuel pump.
The backfiring doesn't really start to happen till I get up around 50 mph. It also backfires when you let off the gas. Any help would be greatly appreciated. Also the spark com computer is currently mounted on the air cleaner and not where it is in the picture.

January 14, 2008.

Hi: The most common cause of a backfire is a vacuum leak. Have you checked everything for that problem? Also, Is it backfiring from the exhaust or the intake? Does it change under different accelerations?