I installed a 1" leveling kit and 265's on my '06 2x4 V8. I'm getting about 16mpg (down from 18.5). I'm planning to install a K&N COI to help it breathe in, and I'm thinking Flowmaster to help it breathe out, but I don't want an obnoxious truck. I was thinking the 50 Series Delta Flow, but I wanted to see if anyone has installed one on their 4.7 V8 along with a K&N, and if so, how it sounds. Also, what kind of mileage pickup did you see? I'm expecting 3 to 4 mpg with the combination, but I want to properly set my expectations. Thanks!
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