Duals or single on a 454
 

I have a 99 1ton crew cab 4X4 long bed with a 454. I tow a 30 foot fith wheel and want to open up the exhaust to let the big block breath.

I have been getting different opinions from the exhaust shops. Some shops say the flowmaster 50 series dual 2.75in, single 3 out is what I should be running for the towing that I am doing, othere say the duafl single 2.75in single 2.75out 40 series will give me what I need.
I've also considered dual cherry bombs, but not sure if that will open it up to much so I loose low end torque.
I am leaning towards the 50 series, but opening up the outlet to 4 inch and dumping in front of the rear passenger tire instead of going over the axel and out behind the tire.

Any advice or suggestions would be great.

I have 3 - 454 trucks - 1 has dual flowmasters, but I am not sure which series because I bought it with them installed already. One of the others has a single dual in dual out Magnaflow and the other has Dual Magnaflows. Personally I like the Magnaflow mufflers better, they give the same performance without as much noise in the cab as the Flowmasters. The Flowmasters at certain speeds have a resonation that sounds like a helicopter, which the Magnaflows do not. I am probably going to remove the Flowmasters and have Magnaflows installed. It is all personal taste - I don't like them real loud inside the cab because I do a lot of highway towing and after a while it gets on my nerves. As far as performance I think they are about the same.

Thanks for the info
 

Thanks for the info.
In the cab noise is one of the reasons I think I am going to stay away from the cherry bombs.

Yeah the Magnaflows help tone it down from idle to bout half throttle, but at WOT it will scream pretty good. I think Mags are perfect for towing. For the 454 I think from the collectors do a 3" single in to the muffler then dual out with no less than 2.5". This will help it breathe and also help keep low end torque. Too much flow will kill low end. And low end is what you need when towing.

Thanks for the advice.
This confirms some of the research I've been doing that I need to keep some backpressure to keep the low end torque.