I would have like to run the 3/4 hole cap, but it was just too loud, so instead I ran the 1 inch funnel insert and it got an average of 90.3 mpg. I believe the stock Spark Arrestor would get something similar to that as it also ran very well. But I'm sidetracked now with the Cobra exhaust.
Gotta tell you... so far the Cobra has yielded only slightly more mileage improvement over the stock opened exhaust which is a super good mod...
...but I'm still in the beginning stages of tweaking it.
