I got my old 79 ford 460 to start & run but its rough and poping and backfireing through tailpipes.what could be causing this new cap rotor & housing new pickup coil new ignition modual .
Could have a partially stuck open exhaust valve. Is there ticking noise coming from the valve cover area of the engine? Could also be stale fuel or dirt in the carburetor. You could have a couple of the spark plug wires in the wrong position on the distributor cap. How long since this engine was last run?
Ignition timing could be off.
I would go with checking the timing.