It started a while back i never could find what and where it was coming from i only knew it was from the pass side sounded like a light pop insde the header, so after swapping the 6al for a 7al3 and looking near the valvcover i see sparks from the spark plug porclen to the hex ( metal area ) of the plug so i swapped that plug out and walla it cleared up the motor smoothed out and no light popping no more exterior sparks, i learned as a kid to watch a engine run in the dark and look for bad wires etc. i guess i should remember simple basic troubleshooting. just thought id share the info