Restricted exhaust

[Magkas]

I just bought a 2015 Sierra 1500 with the 6.2 engine.
I noticed that the cross over pipe, from the left side of the manifold to the main exhaust collector, is substantially "flattened".
It would appear to me that this exhaust restriction ,before the cats,would make any "freeflowing" cat-back system useless.
Any thoughts?

 

[Parts007]

First of all let me say I love flattened exhaust pipes! They are so annoying..

But if you look closely at that pipe, it is all one piece with one cat on each bank and one at the collector. Total of 3 cats on that one pipe.

 

[Magkas]

My point is that with this flattened pipe restriction in place any so called freeflowing exhaust system,after it, would be a waste of money.

 

[Parts007]

Now understood

 

[98trck]

round or oval it should matter as long as the cross section is the same
nascar uses oval pipes on the super speedways