Will be running a 383 miniram. I am going with the SLP 1 3/4" headers. Im assuming these come with a 3" y-pipe correct? If so, will I have any problems running a mufflex 3.5" catback? Im going to take the cat out and put in a straight pipe....can I just use a pipe that goes from 3" to 3.5"?

 

If the design is the same as the 4 inch, most likely, all you'll need to do is put in a 3 in pipe about 12 to 14 inches. The mufflex system has the reducer from 3.5 to 3 already build into the system so you won't have to have anything specially made. Good luck!