[chevyman06]

hello everyone. I am about to install 2 forty series flowmaster mufflers on my pickup, and the mufflers have a 3 inch inlet and outlet, but my current setup uses a 3 1/2 inch pipe, could i just down size my pipe with an adapter? Or would that cause flow troubles? by the way this is my 2002 CHevy with a 6.0 Liter vortec engine. Thanks to all!

 

[Neophyte]

It will cause a flow restriction thereby a drop in performance. You should try to stay with the 3 1/2 diameter BUT check the internals of the muffler too so that also has the same diameter.

 

[Siggy_Freud]

I dont believe it will create a drop in performance that you'd ever notice.

Your going to run dual 3.5 inch exhaust? If so thats way more than is needed for your setup. A little backpressure might do it some good.

 

[ChevelleSS_LS6]

3.5 inch exhaust on a 6.0, (~364c.i.) is freekin' huge! That thing must either be modified sick or have no torque. 2.75" is the biggest I'd use. But, how's that 3.5 inch work for ya?

 

[chevyman06]

well the current exhaust is dualed to the muffler ( 2 cats before the muffler, i beleive that those are 3 1/2 inch pipes also) and 2 outlets out of the muffler, then they form a Y into 1 pipe, a 3 and 1/2 inch pipe. This is the stock system with the stock vortec muffler on.