I just put the 40 series on mine yesterday, little louder than I want but for the 50 series you need:
offset inlet, center outlet and oval because it fits the best. The stock muffler is 30" long so you will need to add some 2 1/2" pipe as well and have it welded in.
'07 4.7L, QTII, duel power & butt cooker seats, remote start, class IV tow group, tow hooks, factory skid plates, Light Greystone..........Poweraid Throttle Body spacer, 6000K HID low beams & fogs, AVS Rain Guards, Flowmaster 40 muffler, Daystar 2" lift, Bridgestone Revo 2 31" x 10", Cobra CB, front sway bar disconnects
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