I am installing soon a 383 that should be about 475HP. I am going to use either Hooker longtubes or Stainless Works longtubes offered by Hawks. Hawks also offers a y-pipe and complete cat-back system for these headers, which would eliminate a trip to the muffler shop. Or I can go to a muffler shop and have a true-dual setup installed which as we all know entails its own set of issues(clearance). My question is this: Will the 3" single exhaust/y-pipe system cause me to lose a large or small amount of power versus a true dual setup, and if so, how much? I would like to see the most gains I can from this engine yet as stated above,clearance issues can also be quite a headache. I await the ThirdGen Gurus advice.

 

My recommendation would be the pre-packaged cat-back.

There's VERY LITTLE power difference between the 2. But those "other" issues will make or break the usefulness and enjoyment of the car, faster than you would believe. 5 HP or whatever isn't worth having a noisy, leaky, smelly car that drags every driveway and self-destructs the first day you own it, and has access to whatever other parts blocked.