"I have used Champions in cars
"I have used Champions in cars, trucks, boats, lawnmowers and have had problems with all of them, using the OEM part number on older cars and cross reference books on the newer motors.
Sorry, but when a motor comes with a particular plug, I replaced it with the same one and still had problems, lack of knowledge, wrong applications and specs of ignition systems don't really enter into it, do they? I wasn't referring to being "a little bit off" when they had problems, either. They all ran like crap. When I changed to other brands, they ran fine.
Yes, they were gapped correctly, the wires, cap, rotor, points, condenser, coil, etc were checked and repaired or replaced as needed before blaming the plugs (or installing them, for that matter). "