Very faint gains, but you dont have A cat, you have 4. So count on buynig 4 O2 simulators if you dont want a CEL. Not sure, probably not too good, I would get an 18" Magnaflow muffler after that because it will keep the sound down, sound good and deep, and perform better than the stock baffled muffler.
yea i dont know how that would sound, ive heard a 5.3 chevy with no cats and factory muffler, sounded mean at start up and idle, but when he got on it, raspy as hell, and ive had no cats before, and man am i happy that i put cats back on it, gained 3 mpg
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True Dual 10 Series Flowmaster, H Pipe, Maggie Hi Flows (94106) http://www.youtube.com/watch?v=nezTBIV8bOA
Do Not, I repeat DO NOT purchase 4 O2 sims, only 2. You only put them in the rear O2's, if you put them in the front the truck will not run right at all, and the CEL light will be on constantly. The front sensors control the fuel management, and if you put O2 sims in them, they will always read lean, you will get horrible fuel mileage and misfires. O2 sims only go in place of the rear O2's.
Linear Mode
