[Tony Radford]

Hallaluya! Backfiring problem resolved. I finally broke down and removed the suspect header (passenger side) and peeled the copper gasket off the head. It was obvious upon first glance which port was leaking as it was sooty black all the way around. Upon closer observation, I found a small piece of the original paper gasket stuck to the copper, which of course kept the mating flanges from seating properly. I cleaned up the gasket, added some permatex form a gasket and put it back together. Perfect!