Exhaust size for 2002 4.6l V8-Installing new muffler/cat back system

[summs]

Hey all,

I’m looking to upgrade my exhaust some and have been trying to figure out the correct sizes for everything and what all I will need. It’s hard to find a cat back system these days it seems like for the 2002 4.6l V8, they just aren’t making them much anymore. I would want to install the cat back but at minimum just cut the stock muffler and replace it. I have decided on the flowmaster 40 series and I think I need 2.25 center in and 2.25 offset out. Is this correct? I’ll also need to buy a tail pipe section as well if just replacing muffler right? If so what size? A lot of these systems seem to say you don’t have to weld anything but can use clamps. Sorry about the long post but any input would be greatly appreciated. Thanks.

 

[rtk11]

I believe the stock exhaust tubing is 2.25" on both the 4.0 and 4.6.

I replaced my catalytic converter with a Magnaflow "direct fit" catalytic converter which uses 2.5" diameter pipe, I connected that to a Gibson full cat-back exhaust system that was mostly clamp-on. (I have the straight out the back pipe and cut a pipe so it didn't extend beyond the bumper) Very happy, excellent flow and tone, and no drone.