I think I read through everything ..... What I am looking for is will 3" tubing go into the stock y pipe clamp? I am going to do a magnaflow 3" si/so and from what I read I should replace the pipe form the y to the stock muffler with 3" so I am going to do that and then just a dump after the muffler for now untill I get the money to finish in 3" to stock location. I just want to know what I am getting into. Thanks for the help. I have a 2007 screw 4.6l 2wd xlt

 

for the si/so muffler, you should be ok with the standard 2.5" pipe. if you were gonna get a si/do muffler, then maybe you would need 3". but if you do wanna get 3", your gonna have to weld it in as the stock size comming off of the y is 2.5".

 

It will sound good.