I have the 22in oval magnaflow. 3in single in single out with the offset inlet/exit.
With the cam/LT's and no cats its really quiet. Because its a "straight through" muffler it still is somewhat loud at WOT.

I wanted my truck as quiet as possible without running more than 1 muffler. I have a 3in cutout right before the muffler as well so when i need it loud for the track.

Here's a link to the muffler http://www.sfxperformance.com/parts/MAG14578.htm

I have a buddy that works at sfxperformance and he got me a great deal on the muffler I haven't had time/ decent weather to get some vids of the exhaust and open cutout. Hopefully sometime in the near future i can.

anyways... hope that helps

 

I ran large dual 3" Magnaflows with the smallblock and then the bigblock too. Those mufflers flow alright but there a raspy glasspack sound that escapes that makes a cammed engine sound like a tractor when wide open. Did not like that one bit. I tried resonators later on in the tailpipe sections with marginal results. The final solution (still in use today) were a pair of 3" Hooker Aerochambers.
A single 3" muffler is too small for a boosted 496. Dual 3" or single 4".

 

I did the big magna flow. its probably 30% quiter ideling that the flowmaster 50 serise. and probably 50% quiter on the higway.. its still very loud from 1300-2300 rpms. So, im going to try smaller ones in front of it..

I think im getting drone or residence... its just that anoying errrrrr that comes and goes in the rpm range.

 

Just took out the 40 series delta flowmaster and welded in a 5x11x 22 inch magnaflow... much nicer on the highway. Still can tell there is something there at idle but open her up and then it will make some noise. Couldn't beat the flowmaster for in town and piping those kids in ricers though

 

Yeah, that's where I am too. Have the 22" si/so 3" magnaflow and when I put catless lt's on, it was too loud. Put a 4"x14" magnaflow 3" muffler in front and it quieted it down some, but not enough. Going to swap it for the 6" or 7"x14" round magnaflow and see how that goes. I don't have any drone though, just loudness under any amount of throttle input, quiet at cruise though.

 

wow all u guys have got sick tricks must be nice