I am trying to place an order right now on summit but i dont know the stock Y pipe diameter for my 305...

I want to get a slip on cat and clamp it to the Y pipe, then get a slip on muffler to clamp onto the cat and then just some pipe to run it out from under my seats...

basically i really would like to be able to just clamp everything on and not have to pay to weld it, the shops around here rip me off every time.

currently im thinking just some cheap 50-60$ cat verter (cause im in CA and have strict smog) and a hooker aero chamber bolt directly to the cat (to pass inspection and to quiet it down a tad) i have heard that hooker is good and since the muffler is only 60 bucks i decided to go with it, unless someone can show me a cheaper muffler that will muffle just about as good.. heheh..

thanks!!