8.1 Magnaflow Question?

[ss502gmc]

I just had a muffler installed on my truck and sounds good an all except for the in cab drone. My question is they put a dual in single out but it looks like they put a 3 in single out on the muffler and connected it to my stock 3.5" tail pipe? Doesnt seem to make sense to me but it seems like it would restrict the flow. There a very reputable custom shop but it doesnt seem right to me. All i know is its the 24" long magnaflow muffler. Any input would be great as i dont want to be more restrictive than stock. Thanks

[96chevy7.4L]

Well you do need a certain amount of backpressure in a street engine to have good torque. The 3.5 dual in to a 3 inch single out is a lil extreme but you may notice some more grunt.

[alaska511]

See my thread: http://www.gm-trucks.com/forums/index.php?showtopic=112644

 

I wish I had done this when I had my 8.1, I went through 3 mufflers before I quieted that headache down.

[04JJHD]

i just put a flo pro 2505 on my truck (2004 2500hd with the 6.0) and i love it!! it's got a good rumble to it and just crusing it's hardly even noticeable, between 2000 and 3000 rpms it has a real nice deep rumble.

[ss502gmc]

I finally crawled under my truck and measured the dual in single out muffler and it actually is dual 3" in and a 3.5" out, i guess it looked smaller because they got rid of the little y pipe after the muffler. But i must say i noticed a considerable increase in power especially when towing 15,000lbs. I am pleasantly surprised. Im still trying to get used to the drone but for the difference it made with the throttle response ill get used to it. Its way better than that oil drum that was under there before!