I'm in Maine so the weather conditions last Friday night was cool (60s into the 50s) with low humidity. Car weights 2680 without me in it. I based the jetting upon plug color. After the first run the plugs had no color at all to them. After upping the jets two sizes still wasn't much color to them so I went up two more. Didn't check the plugs after that as we were going into eliminations and I didn't want to make any other changes. However, I will say that each jet change resulted in a better run.