Quieter 4 inch muffler

[Walter R. Malik]

Bit of an oxymoron but had enough raunchiness of the straight through Flo Pro muffler. Different application- it's a street 383 cid truck but there's a lot of experience here. Before you say it the wrong pipe size, you're probably right but for now it's staying. Have about 24-40 inches length to play with. Not sure if a better quality Magnaflow (straight through) will be any different, probably looking at Donaldson chambered diesel type muffler or a 'bus' muffler. Advice welcome.

Personally, I would use a straight through, Gibson #788040S which is 30" total length and has a 8" round body 24" long.
The "S" is for stainless steel but, they also offer that muffler in aluminized mild steel; same number without the S.

I think it is a High Performance, Motorhome type muffler.

[Racer71]

I think on a single a magnaflow would suit you well, I’m kinda curious about using diesel truck type muffler now since it’s been brought up. They’re not shaped or made like a typical automotive performance muffler but there’s not the typical shortage of space on a truck that limits design of car muffler either. I wonder how the flow numbers compare.

[milenkogt]

Borla XR1 "sportsman" variant are great options. The multicore version is very similar to their ATAK line which is downright loud.
Oval cases are around $160ea


Another option is Vibrant Performance mufflers. They are all 304SS cases and straight thru. Around the $125ea range

[dfarr67]

Ordered a Donaldson 4 x 34in type 1 muffler- don't have model off hand. will let you know how it works out. $150 so not a big outlay.