Those jets do sound big for just 1 baffle drilled but I don't think thats your problem if your mileage is that bad. Those are the jets I run with 48 pilots and I get better mileage than that. I have totally gutted pipes with just the reducer cone left in with pod filters.

I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!