Smoke from Drivers Side Tail Pipe Question

I recently purchased a 67 Dart GT bucket seat automatic console car. It has a 318 that prior owner said came out of a 73 Dart. It has an old Edelbrock intake manifold, old Edelbrock carb, rusty old headers that sound like they are leaking on the passenger side of the engine, and new dual exhaust. The drivers side exhaust and passenger side exhaust are not connected. Blue smoke is coming out of drivers side exhaust and it is making a popping backfiring noise out the drivers side tail pipe. Passenger side exhaust does not do this. What is the cause of the smoke and backfiring from drivers side exhaust? How is this problem corrected? How much will it cost? I live about 20 miles east of downtown LA.