Mufflers for 2005 workhorse with GMC 8.1

I would suggest Flowmaster

Hank MI wrote:
It's typically a combination of the sound level you're trying to achieve and the engine. Too little back pressure, not really a concern, maybe if you're running open headers. With a full exhaust system, stock exhaust manifolds, catalytic converter, mufflers, it's nothing to worry about.

So it comes down to what fits and what sound are you willing to put up with. Any stock type muffler that fits should be good. If you're willing to put up with a little more noise there are other options. You probably won't even hear the difference from the driver's seat and they can improve performance, marginally.

Thanks Hank. If I have to replace the mufflers anyway, what muffler options do I have? I sure wouldn't mind a little improved performance

rgatijnet1 wrote:
Yes, mufflers are usually designed to fit the space available and provide the correct amount of back pressure. Too little back pressure can eventually burn the exhaust valves and too much can cause the engine to lose power, etc.

This is another old wives tale. Your valves work better with no back pressure. The better exhaust systems/headers actually create lower pressure at the valve that promotes better exhaust scavenging.
Bill

It's typically a combination of the sound level you're trying to achieve and the engine. Too little back pressure, not really a concern, maybe if you're running open headers. With a full exhaust system, stock exhaust manifolds, catalytic converter, mufflers, it's nothing to worry about.

So it comes down to what fits and what sound are you willing to put up with. Any stock type muffler that fits should be good. If you're willing to put up with a little more noise there are other options. You probably won't even hear the difference from the driver's seat and they can improve performance, marginally.

It is more of a combination between the power train and the type of vehicle.

Yes, mufflers are usually designed to fit the space available and provide the correct amount of back pressure. Too little back pressure can eventually burn the exhaust valves and too much can cause the engine to lose power, etc.