Everyone convinced me the problem with my son's '65 was not a head gasket. After taking plessm's advice, the car is once again running great. I replaced the plugs with Autolite 45's gapped down to .035. Replaced the cap/rotor, and plug wires. The car is running as good as it ever has. I guess I learned, like plessm, that you can't run that big of a gap, just because you have a flamethrower coil. I previously was gapping the plugs at .040, but not any more!