Flowmaster for ls1?
It's a low rumble at idle (louder then stock for sure). It's loud when accelerating (but not quite loud enough to get pulled over for). It absolutely screams at WOT (be careful because you can get pulled over if a cop hears you go WOT with this setup).
Best part is the price. $150.00 installed if you like your current tips and $250.00 installed if you wanna give yourself a new set of stainless steel tips.
Best mod I have done so far. I absolutely love the sound, it was cheaper then all the conventional catbacks and produces as much HP as loudmouth without the drone and more then the others.
PM me if you need part numbers and details on how to do it.
anybody interested go to Parts for sale under
Magnaflow muffler and bullet for sale.
The Best V8 Stories One Small Block at Time

Granted it does not flow as well as most other aftermarket mufflers available for our cars, I have still seen healthy gains(10+rwhp) over bone stock with the AT cat-back. Like most other systems, just replacing the muffler only won't really net you much of a gain anyway. Where I think the Flowmaster hurts you is on cars making 350+rwhp as the dyno has proved this.
Either way though, it has a really deep tone(which I personally do not think the Magnaflow or most other systems have).
How does the dynomouth sound on the highway..in the cabin that is. I travel in my car and don't want something that drones like a demon. I may just end up going to a cut out.

Really like your username, but your opinion on Flowmaster is crazy talk.
The Flowmaster did sound nice though, and for a stock (or nearly) setup I wouldn't think it would COST you HP...just not as good a muffler as some others.
Why do I have this opinion?
Because I love drag acing, and love the sound of a good V8, Flowmaster system was originaly designed for the LT1, that is why it sounds so nice on an LT1. Flowmaster's muffler choice on a LS1 was quite stupid. It sounds nice at cruise, quiet at WOT, and like **** when you rev it.
I plan on getting Dynomouth put on in the next month, and do not plan to ever think of getting the system again. It is bad for power, doesn't sound all that good, and looks ugly at that too. Never buy Flowmaster, unless you for some reason love it. I hate it, and plan to sell it soon and will not recomend someone buy it. But I am sure someone out there still will.



