I understand that. To my Knowledge I am good at what I Do! I go through many test on vehicles from plug gap to heat range to air bleed to jetting and so on. And Plugs are a big roll in tuning after a pass. And most of the time Im right on! And Then I check them with a wide band meter . Just Remember the best racers in the early years didn't use any kind of meters it was all knowledge and knowing your engine when it was hurting and what didn't hurt the engine.
