B4 I make a valid attempt at installing these headers does anyone know if they ACTUALLY fit? I want to hear from people that have installed them on a 3500HD 4x4 6.0L Crew Cab LT Dually.

 

Ok I just looked at everything and I think the headers will work. The ORY cant be for my truck's stock catback. My stock exhaust coming off the stock manifolds show a pipe running from each manifold going into a single HUGE muffler and from the muffler one pipe exiting. The y pipe that was sent looks like it was designed for a truck that plans to go with a custom catback.

 

If they fit a 2500HD 4x4 with the 6.0L then they will fit your truck. The frame is the same, but the 3500 just has stiffer suspension.

 

Sounds good. I do know the ORY is not for my truck. Only one pipe comes out of the Y and my truck shows two pipes going back to the muffler.

 

if you're getting rid of the cats, you're going to need a retune.

 

The Y pipe is probably the same one I have. Its made to mate to a stock 1/2 ton catback.

 

Its an iffy on getting rid of the cats for now. My buddy said he can fab up an intermediate pipe with or w/out the cats.

How much of a gain minus the cats? If it is not that much I am keeping them.

 

your biggest gain will be a tune . . . . there's so much that is left on the table with a stock tune.

removing the cats 5-10, but I've never seen anything dyno proven

 

Id ditch the cats, ur there and doing it you mise well do the job and not have to go back in a year or sooner and cut them out cause they plugged up or somthin stupid like that.

 

What about hi flow cats?