For the 5.7 I think the inlet is 2.5 and the outlet is 3. I'm not 100%. But it all depends on what muffler you get. You need 2 in (one pipe from each header to the Y) and then 1 out (Hence "Y" pipe) for a typical muffler. If you're doing true duals then you would need an H pipe or an X pipe

 

I already have a flowmaster 40 and duals going out of it, but its a really crappy job, but itll have to do for now. and would i have to change all of that if i put this in? my muffler is single (3") in and dual (2.5") out also

 

No no. You would only have to cut out the stock Y pipe and weld in the new one. Any muffler or exhaust shop should be able to get it in there

Here's a pic of it installed:
http://i966.photobucket.com/albums/a...Mamba/Y-04.jpg

 

For some reason, mine looks alot more cramped underneath there?

 

You could do as I did and do away with the y pipe altogether. Get the muffler shop to come straight from the cats, with two 2.5 inch pipes to the muffler location then use a dual in dual out muffler and dual tailpipes. Works great and no h or x pipe is needed. I did have a x pipe muffler at one time, but see no change since I replaced it with a regular dido muffler

 

yeah. if i did that, i would need to get a new muffler also. which i wasnt really planning on doing but i do have one question, did running those two pipes make it any louder?

 

It's definately louder than stock, but I believe when mine got the loudest was when I replaced the stock cats with magnaflow hi flow spun converters. The stock cats are very restrictive compared to the magnaflows. I have shorty headers from BBK but they didn't make it louder than stock, until I added the hi flo cats. You can buy a dido muffler for around 50.00 or less, and you will get better exhaust flow from using two pipes than the 2 into 1 that comes from the factory, and depending on what muffler you use, it should be louder than what you have. Good Luck

 

Right now i have a flowmaster 40 single in, dual out. And im in college so im not to well off on funds at the moment but im hoping to get some pacesetter headers sometime soon also

 

Pacesetters are gonna cost more since they are Longtubes. And you'll have to either delete your cats or relocate them so if you're tight on cash I would either avoid LTs or wait until your financial situation gets better.

I know, I'm a college student as well

 

I was looking at the pacesetter shorty headers