Bigger y pipe

I recently purchased a set of your headers with the factory connect y pipe.
Do you have a larger outlet y pipe available ?
I'm currently running an mbrp 3.5" cat back, seems like a bit of a sin to go from those 3" collectors and lead pipes to a single 3" outlet on the y pipe.
I would go as far as to suggest that the factory connect y pipe be a 3.5" outlet for at least a few inches before stepping down to 3" for the factory connection.
That would allow folks more flexibility in the future.
Is anything like that available ?

Vibrant makes a stainless dual 3" inlet to single 3.5" outlet that I have ordered.
The whole dual 3" collector to single 3" thing was wrecking my state of mind...

I'm sure one of the fancy engineers around here could explain why it is perfectly fine having the two 3" leads drop down into one 3" pipe. I'm not an expert on exhaust design but I do trust the guys at Stainless Works to design a product that works to the best of their ability. It's not just SW either, Kooks and ARH have the same sizing standards for our trucks.

Rookie said:

I'm sure one of the fancy engineers around here could explain why it is perfectly fine having the two 3" leads drop down into one 3" pipe. I'm not an expert on exhaust design but I do trust the guys at Stainless Works to design a product that works to the best of their ability. It's not just SW either, Kooks and ARH have the same sizing standards for our trucks.

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I can confidently say it is not okay, but it was designed to adapt to the 3" factory exhaust, so not their fault at all.
If you have anything but the factory exhaust to connect to though, a larger y pipe is going to be beneficial.

So kooks, SW, and ARH who all make kits with 3" leads off the headers and typically drop down to a 3" y pipe are wrong? Lot of people get concerned about back pressure issues as is with just running a resonator or a simple turn down even though many have said it is not an issue. If I was that concerned with the fact that the volume of air exiting was being restricted I'd go with a true dual system. The volume of one 3" pipe per inch is 7.07 cubic inches meaning the two leads have 14.14 cubic inches of volume capacity per inch of pipe. A single 3.5" tube only has 9.62 cubic inches of volume per inch. 2.55 cubic inches more than a single 3" but 4.52 cubic inches less than dual 3" tubes. I guess the questions falls on back pressure. How much is required before you have issues? None? That I'm not sure about. I do know the biggest difference you'll see from altering these sizes is sound though.

Do you have a dyno you could do some runs on? I'd be curious to see comparison numbers between the two setups.