James Heaton
Junior Member
I have a 2017 5.7 Regular cab Express with the 8 speed. I cut the y pipe and built dual 2.5 inch off if it with a close quarter x pipe. Followed it up with dual 2.5 to two Thrush welded chambered mufflers (35 each at Oreilly's) and finished off by connecting to the factory tail pipes at the muffler exits. Its a little loud when its backed up to the garage. Not like those damn Mustangs with straight pipes but, still a little loud. I'm noticing the trans downshifting when I come to the light now. guess I never heard that with the school bus muffler?