autocomman

So ive been reading on exhaust size and the 6.0 People removing stock mufflers and loosing low end torque and having very drone trucks...I need to keep my conversion smog legal and the 03 silverado 2500hd my motor came from had 3 inch cats. 2.5 right off the manifold flanges to 3 inch cats then Y together. I picked up 2.5 inch pipes ill going to y together to a 3 inch and 3inch out the back. Ill probably have to up the size of the y to 3 inch, or i may keep the exhaust 2.5 and just step it up and down again around the cats.

This is in a b body wagon, a giant box so i need to keep it quiet, much noise and it will drone inside. Any recommendations on mufflers or exhaust size suggestions? I dont want to do headers as keeping it smog legal becomes an issue. s it is i have to mod the stock manifolds to fit as i dont wanna spend the $$ for F body manifolds. and at the referee that may be an issue if they catch that ive got camaro manifolds on a truck engine

oldgoat69

Cats will help keep the noise down as will a cross over after the cats. If you plan to go dual take a look at Gibson mufflers in a 2.5". They are some of the quietest I have run into, very little drone as well(the crossover helps here as well). Most of the 99-current GM trucks I have seen have a single 2.75" tail pipe.

autocomman

Its gonna Y 2.5" off the flanges with cats into a 3" pipe to the rear, gonna keep it a single in the stock location. Ill look into the Gibsons though

i r teh noobz

iTrader: (4)

Pick a quiet muffler and it should be fine. I run 2.5" Y to 3" single out with no cats, no flex pipe, solid hangers, and a 3" Borla ProXS in my Z. Its hatchback so it suffers the same fate as your wagon. Volume and drone were tolerable before the H/C swap, so as long as your engine is stock I don't think you'll have much issue.

autocomman

Fair enough. One thing thats nice about it is that is it a relativity quiet car for its size. Id like to keep it that way.

oldgoat69

Based on this layout a long single 3" Gibson should be as quiet as possible with great flow and low restriction.