Installed a Flowmaster muffler today. Was a little concerned about drone and being to loud. None. Selected series 50 big block, dual 2.75 in, dual 2.5 out, installed with stock tailpipe that collects both outlets. Perfect, no drone and quiet as stock inside.

 

Was everything else stock? I need to replace mine, but I want it quiet as I can get it. Where'd you purchase it? Mine is 1 inlet and I outlet though. 08 H2.

 

Mine is a 06. Like I said quiet as stock. Flowmaster has a Series 50 big block with single in and out 3.5 inch. A good exhaust shop should be able to help you out. I measured my pipe size, found best price on internet, 214.00 and had it installed for 85. The series 50 big block is the quietest muffler they make.

 

I wonder if there are some other differences in the BB 50 series. I put one on my 03 and it was a LOT louder than stock. It sounded awesome but also had an unpleasant drone at highway speeds. Soon after that I got lucky and scored a new old stock GM Performance Parts stainless cat back system (Borla touring muffler) and installed that along with full long tube headers. It was quieter with the headers and Borla setup with no drone (also improved performance nicely with a custom tune) but that was a lot more involved than replacing just the muffler.

 

When I purchased my 08 the previous owner had installed a 40 series flowmaster. It was immediately removed and replaced with a Walker factory replacement as a GM original part is no longer available.

I could not stand the noise nor the droning the flow master created. It actually ran better after I replaced it. My guess is the flowmaster probably flowed better removing some of the back pressure needed to provide low end torque.

Beside, who runs an H2 at 4k. I realize this is a matter of owner preference but I like the low end sound the factory muffler provides and when I do need to jump on it performance is more important that noise. Stealth is good!

 

Agree to stealth. I was skeptical of doing the change but the series 50 big block, not 50 HD or Delta flow is quiet as stock. My aftermarket air cleaner intake tube has more noise. My son put a 40 on his Silverado, hates it. I can’t tell the difference with the windows down on my h2. Install shop asked if I wanted to keep my factory muffler, after start up, I said to recycle.