Chevrolet Repair: 82CHEVY TRUCK BACKFIRING IN CARB, hei coil, spark advance

Question
WHEN I STARTED THIS PROJECT IT HAD THE SAME PROBLEM IT DOES NOW EVEN AFTER I REPLACED HEADS, INTAKE, DISTRIBUTER, HI PERF HEI COIL, AND TIMING CHAIN AND GEARS. IT WILL RUN ALRIGHT AT AN IDLE IN PARK, BUT AS SOON AS YOU PUNCH THE GAS IT JUST POPS AND BANGS. EXPECIALLY IF YOU HAVE IT IN GEAR W/ FOOT ON THE BRAKE. POPS AND BANGS CONSTANTLY WITH LOAD ON ENGINE. IF YOU COULD HELP SOLVE ANY OF MY PROBLEMS, IT WOULD BE WELL APPRICIATED.
                                THANKS
                                WILLIAM  

Answer
without performing the ignition system spark advance test procedure via a timing light and the procedures designated within the repair manual it could be numerous faults  from the spark advance module on the firewall to the knock sensor if installed on your particular vehicle to the computer to a faulty wire at one of the computer connectors.

Without performing and checking all these possibilities an exact cause cannot be made.

You may also want to check to be sure that there is not a broken ground wire that is supposed to be connected on the backside of the cylinder head against the firewall of which is very hard to see without a mirror.