I'm used to seeing everything with a stock Y pipe and 4 cats. I've never seen an exhaust like this. Just got the truck about a month ago. Not sure if it's stock or not. It's pretty beefy. Looks like 3" all the way back to the muffler with the cats pretty far back behind the cab and staggered. Dual into the muffler and a single out. I found a Gibson Muffler back with dual in and dual out. But that's a side note.

Anyway.. I was looking at Long tubes and couldn't find a catted Y unless it was a $1400 Kooks or ARH setup. If I were to get a set of LT's how much fabrication would this require to plug into a slip fit 3" collector? I won't worry about the cats now, knowing that they're just down stream a little more.

Pic of mine for reference. It looks pretty stock. Just used to seeing the cats right behind the manifolds.

 

Yup, thats all stock right there.

Welcome to GM's great way to pass emissions.

Early 6.0's got the big pipes and converter that were way far away from the manifolds.

 

Ahhh.. I gotcha.. would require some fab work or full aftermarket to accommodate catted LT's then? I want cats to keep the mirrors at the inspections happy and to keep the rasp down. Quiets it down a touch. I did the ORY deal with my Camaro for a long time and it was just too loud after a while. Too hard to shut it up without adding the cats.

 

Yeah some exhaust fab work and you should be able to get everything to work for you. You'll just have to hack off the pipe in 2 spots and remove the rest from the factory flange, then drop the LT's in, do some measuring and weld in the new pipes to connect to the headers.

Lucky for you that piping it already like 3in.

 

ARH offers a set of longtubes that are a direct bolt-on..no fab work needed..go their site and look under 99-06 6.0 trucks with dual pipes..i bought the same kit for my 06 gmc vortecmax 4wd..however..im now wishing i would have went with the 3" y-pipe..seems most guys on here are getting a lot better numbers on a 3"-3.5" single exhaust...even after cam swaps

 

^ Right on!

It probably helps with a little more back pressure, as long as it's a good quality Y pipe not two pipes slammed together.

 

Back pressure is like a myth.

 

Unless you are just wanting to use the stock muffler id go with a y-pipe..they make catless and non catless pipes