Interesting, mine is a Y into a single inlet muffler and I haven't had any issues so far. I've been shopping cat back systems to put on when I do my JBA headers and had settled on the gibson stainless with a single inlet muffler. I haven't read or heard of any issues with these systems on the V10 yet so I still plan to go with it.

 

I'm thinking the guy at the shop could be full of it! I am thinking about just getting the Y pipe and install the Magnaflow kit myself. The kit was designed for my year truck and with the V10. The only difference is my truck doesn't have the Y pipe at the Cats. I would assume that the Magnaflow knew what they were doing when they put the kit together?!

 

That's what I'm thinking. They designed the system to work on a certain vehicle/engine combo and to then come back and say it's risky sounds very odd. Especially when the stock system is designed with a 2 cats into 1 muffler. The stock muffler has to be more restrictive to meet sound levels than the magnaflow design, so again it's kinda weird to hear that.

 

I think you have two pre-cats, one post cat, and then a muffler further back?

 

Not on my truck, just the 2 cats and the giant muffler.

I did look in the parts manual. The 49 state trucks are supposed to have 2 cats going into a 2 inlet muffler then out the single tailpipe. The california emission trucks are supposed to be 1 cat into a single inlet, single outlet muffler, so it looks like my truck is kind of a mongrel. Either at the factory or a dealer at some point installed a single inlet Mopar muffler on it.

 

What size inlet/outlet is the new muffler? If it's 3" in and out then it sounds like the shop knows nothing about exhaust and flow. Figure you have a two-in one-out muffler,mbut the out is a 3", meaning it's the best the exhaust will ever flow, regardless of the inlets. So if you're putting on a 3" or larger muffler it doesn't matter since 3" anywhere in the exhaust will be the same or better than factory.

 

The Magnaflow kit I have is a 3" single inlet with a 3" single outlet muffler.

 

That should be plenty.

 

^Yep. Either way you end up with a 3" exhaust, might as well use a much better flowing Magnaflow muffler.

 

my V-10 has the same exhaust, as you can see. I have been itching to replace the stock system as I do not have enough power and the shop says I need 2 cats installed at a cost of around $1000!!!