Whats the best size pipe for a 350. It will one day have headers, cam ext.. But right now its pretty stock. Right now im using the v6 exhaust from what it had originaly to the car. Im thinking 2 1/2 straight back with flowmaster. But I have seen like XPipe with other mufflers

 

I just did mine a few weeks ago but it's a convertible. It's a bone stock 350 but will change the cam if the timing chain goes. If you're going to do duals, remember that the driver side exhaust manifold flange is 2" and you have the crossover pipe that you need to block off on the passenger side exhaust manifold. Or buy the exhaust manifold from Thorntons that has the 2 1/4" flange that has no cross over to block off. They do sell only the driver side manifold if you like but you still need to block off the passenger side. My pipes that I bought from Motorcity Supercars/Inline Tube fits perfectly. I bought the head pipes and tailpipes and use Dynomax Super Turbo mufflers. Sounds great with no drone. It's not very loud and has that smooth rumble sound. These pipes has no mandrel bends. But you can use Pypes or other name brand with the mandrels. Other guys will chime in with their thoughts.