My truck is a 2010 with the lc9 5.3 motor. Right now my exhaust setup is tri-y headers, no cats, with a 3" straight through magnaflow muffler welded in the stock location with the factory tailpipe cut off right after the axle pointed down. I noticed a good low end gain from the headers, but my top end seems a little lacking. Basically, im 3" from the y-pipe to the rear of my muffler and then it's reduced down to the factory 2.5" tailpipe. Based on some calculations, my motor needs a 3" single exhaust. Would I gain anything by running a 3" tailpipe from the muffler back?

 

Im against goin down to a smaller tailpipe personally .. I think and only think based on every write up on here u shid scrap that 2-1/2 and run 3" or bigger on the tail pipe .. Im 3" thru a 4" muffler(3" inlet and outlet) and into 4" bend 60degrees out right in fromt rear tire wit a big *** tip(no lie i have 7" stainless tip) and no drop in power from seat of paints feel on top end .. Jusy my opinion and my 5.3 in sig

 

I also am against going to teh smaller tailpipe.

Disregard my advice on the "other" site. I thought the 2.5" size was out of the cat and the rest of the exhaust was 3".

peace
Hog