I installed a new set of pipes, & also a new set of spark plugs at the same time so I could see how they're burning. How many miles should go by before I can see how they're burning?
Reading plugs isn't what it use to be. Mostly today you will see color on the plugs from the additive packages which means nothing as far as mixture adjustments or AFR. The tetraethyllead is what use to give you the color when tuning in the years past but with the removal of that additive, the color is not indicative of fuel mixture.