so...now that I just bought a stock "Y" pipe from silent1....does anyone know any reason why it won't bolt up to my exhaust system (I am replacing the duals with a single to improve my aftermarket exhaust choices)

the "Y" is from a 2001 5.3 and mine is a 1999 6.0.....since the manifolds are the same and the block is the same dimensions the exhaust "Y" should just still bolt on right ??

 

The collector flanges should be the same from what I remember.

What are you limited to headers? Nothing is wrong with The Other Guys that work for the 3" dual headpipes...

 

I am not limited on headers.....it's everything from the cat back that I am limited on

as far as I can find NOBODY but Magnaflow makes a catback system for the '99-'01 6.0 trucks (that one requires cutting and welding and I've had enough of that for now)...I want a bolt-on cat-back system that sounds good and won't kill the bank account, and I just can't get that if I stick with the stock 2 3/4" duals that are on there now....

as for headers....TOG headers and the like are really nice but I think I will stick with shorties, they don't give the improvement that long-tubes do but are a direct bolt-on and will keep CARB happy ( I DO live in Kalifornia)

I'm pretty certain that if people can make 500-600 RWHP through a "Y" pipe I can run one on a 6.0 NA motor without any performance hit...hell, I might even pick up some low-end torque due to the smaller pipe size

 

Well you can make a cat-back at a local muffler shop for far, far less than a bolt on "in the box" one.

I thought the Thorleys were CARB legal? I know most of the other LTs aren't.

You can make tons of power through a Y-Pipe for sure. I think that single 2.75" outlet will have some restriction for you. 2.5" pipes to a 3.5" collector would flow a ton...easily support over 400rwhp or more.