I'm about to order a Flowmaster for my '02 LS 3.4 and cannot seem to figure what the factory exhaust piping size is. I'm assuming 2.25" and have seen some others "assume" that as well, but nothing solid. Can anyone confirm it is indeed 2.25"?

Also anyone have any advice as to whether I should go with a 2 chamber or a 3 chamber flowmaster muffler? The cat is gutted on it and it has the factory resonator. I don't want it to be raspy or obnoxious, but I do want it louder with a throaty tone.

 

Just following up with my findings after having my muffler installed.

I bought a 2.25" Flowmaster muffler and watched the guy install it. He installed with no sizing issues and everything fit fine.

 

Flowmaster deltaflow 40 series sound great