Recommend a muffler for 1986 Chevrolet K20 350SBC

Creekside

Creekside

Joined
Jun 12, 2020
Messages
1,673
Location
SW Missouri
I'm needing new mufflers for my service truck as the old ones basically rusted off. Trying to decide if I shell out the $ for the Walker 21910 Quiet-Flow Stainless mufflers that it calls for or go with something on Amazon. The tail pipes will have to be replaced anyway so I'm not tied to the original style muffler. It's a 2.5" ID inlet. I like a little rumble or even some cackle at idle but don't care for how a glass pack sound on the highway. I have a flatbed on the truck so lots of room to play with.

Any recommendations?
 
Creekside said:
I'm needing new mufflers for my service truck as the old ones basically rusted off. Trying to decide if I shell out the $ for the Walker 21910 Quiet-Flow Stainless mufflers that it calls for or go with something on Amazon. The tail pipes will have to be replaced anyway so I'm not tied to the original style muffler. It's a 2.5" ID inlet. I like a little rumble or even some cackle at idle but don't care for how a glass pack sound on the highway. I have a flatbed on the truck so lots of room to play with.

Any recommendations?
Click to expand...
whatever aftermarket exhaust you go with (i’m a magnaflow person) use a Vibrant ultra quiet resonator infront of it. they’re pricy but it’s amazing what they can do for tone and decibel restriction. i have two on my free breathing 6.0 silverado before two 16” magnaflow bullets.
 
Creekside said:
I'm needing new mufflers for my service truck as the old ones basically rusted off. Trying to decide if I shell out the $ for the Walker 21910 Quiet-Flow Stainless mufflers that it calls for or go with something on Amazon. The tail pipes will have to be replaced anyway so I'm not tied to the original style muffler. It's a 2.5" ID inlet. I like a little rumble or even some cackle at idle but don't care for how a glass pack sound on the highway. I have a flatbed on the truck so lots of room to play with.

Any recommendations?
Click to expand...
If it will fit. 2 1/2" Duals? Add a crossover over pipe, an "X" pipe, not an "H" pipe.

https://www.summitracing.com/parts/wlk-17749

I have used them before with great success, no drone. Lifetime warranty, but I never had to utilize that feature.

Magnaflow sucks. :devilish:
 
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You seem to be really concerned about budget since you mentioned a Walker Quiet-Flow as the one you'd rather not spend money on and instead try to find something cheaper off of Amazon. You get what you pay for.

The Walker muffler is essentially a stock style replacement and will be relatively quiet. Since you don't mind a little rumble I'd go with a "Super Turbo" style muffler. If you want name brand you can go with Magnaflow or Dynomax, but even Summit Racing makes their own version. The cheap no-name Amazon/ebay ones just don't last. The fiberglass blows out and it sounds like crap after a while, then the internal metal stuff starts to disintegrate...

The Super Turbo style mufflers are a little better flowing than stock and will give a little performance rumble, but nothing like a straight through style muffler.
 
Walker Quiet Flow SS if you don't want loud. Flowmaster, Thrush, Dynomax, Magnaflow, all of those will be louder than stock. Don't buy the cheap Amazon junk, you WILL be replacing it in a year. The Quiet Flow lasted a few winters for me on my Jeeps where the Amazon mufflers and Flowmasters lasted one before rusting out.
 
Creekside said:
I'm needing new mufflers for my service truck as the old ones basically rusted off. Trying to decide if I shell out the $ for the Walker 21910 Quiet-Flow Stainless mufflers that it calls for or go with something on Amazon. The tail pipes will have to be replaced anyway so I'm not tied to the original style muffler. It's a 2.5" ID inlet. I like a little rumble or even some cackle at idle but don't care for how a glass pack sound on the highway. I have a flatbed on the truck so lots of room to play with.

Any recommendations?
Click to expand...
Spintech Mufflers. They have many different sound levels and patterns available, along with galvanized & stainless but their sound quality is unmatched. Your truck will have a much better sound under WOT but these don’t drone. Check them out!


https://spintechmufflers.com/
 
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AdmiralYoda said:
You seem to be really concerned about budget since you mentioned a Walker Quiet-Flow as the one you'd rather not spend money on and instead try to find something cheaper off of Amazon. You get what you pay for.

The Walker muffler is essentially a stock style replacement and will be relatively quiet. Since you don't mind a little rumble I'd go with a "Super Turbo" style muffler. If you want name brand you can go with Magnaflow or Dynomax, but even Summit Racing makes their own version. The cheap no-name Amazon/ebay ones just don't last. The fiberglass blows out and it sounds like crap after a while, then the internal metal stuff starts to disintegrate...

The Super Turbo style mufflers are a little better flowing than stock and will give a little performance rumble, but nothing like a straight through style muffler.
Click to expand...
It’s not so much the price that concerns me it’s the lifespan. I read some pretty lousy reviews on them and have a hard time spending that much more for OE style if it’s going to fall apart in 3-4 years. That’s why I questioned just ordering something off Amazon.
 
I have the Summit turbo mufflers on multiple vehicles, the longest is 5-6 years now. However, these are not run in a winter salt environment.
 
This is a square body right? Seems like exhaust kits would be all over the place for it... doesn't seem to be the case in a quick search though, maybe its the "k" part or the "20" part.

Flowmaster does make tail pipes for it

Does it have duals? Headers?

A stainless 50 series would be a nice muffler as would a Ultra Flow, but either makes the Walker seem cheap.
 
FWIW I just installed a Dynomax catback (albeit on an '04 Ranger V6) and was overall impressed. Nice little rumble and good fit. I've personally never heard a Flowmaster I like ‐‐ too redneck for me, but that's probably because I identify as white trash, not redneck.

Anyway was my first experience with Dynomax and I was overall mostly impressed.
 
I thought the Flowmaster was a very nice build on my Ranger. Near OE Fit.

It was a little droney in this application (but not like 2 chambers on a Mustang) but I may well put it back on. The dynomax kit (I also have) is sorta pitiful by comparison from a build stand point, but it was also A LOT cheaper.

 
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Reactions: D60
Borla. It's 304 stainless, so it will last forever :D

If you care about lifespan, then 304 is a must.

Borla #400484 seems like the best muffler to use for your K20.

DuckRyder said:
I thought the Flowmaster was a very nice build on my Ranger. Near OE Fit.

It was a little droney in this application (but not like 2 chambers on a Mustang) but I may well put it back on. The dynomax kit (I also have) is sorta pitiful by comparison from a build stand point, but it was also A LOT cheaper.

Click to expand...


Both the Flowmaster and Dynomax are aluminized steel. It's ok for the Dynomax since it's so cheap, but unacceptable in the more-expensive Flowmaster, which is priced too close to the 409 Magnaflow and the 304 Borla :sneaky:
 
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slacktide_bitog said:
Borla. It's 304 stainless, so it will last forever :D

If you care about lifespan, then 304 is a must.

Borla #400484 seems like the best muffler to use for your K20.



Both the Flowmaster and Dynomax are aluminized steel. It's ok for the Dynomax since it's so cheap, but unacceptable in the more-expensive Flowmaster, which is priced too close to the 409 Magnaflow and the 304 Borla :sneaky:
Click to expand...

That flowmaster is 409 as are the pipes. The Dyno max I have has an Ultra Flow SS muffler but the pipes are aluminized. I also have Ultra flows (not welded) on the F100 and really like the way they sound but they are pretty loud. Anyhow.
 
DuckRyder said:
This is a square body right? Seems like exhaust kits would be all over the place for it... doesn't seem to be the case in a quick search though, maybe its the "k" part or the "20" part.

Flowmaster does make tail pipes for it

Does it have duals? Headers?

A stainless 50 series would be a nice muffler as would a Ultra Flow, but either makes the Walker seem cheap.
Click to expand...
Yes it's a square body. Factory duals but on stock manifolds.
 
TheLastWord said:
If it will fit. 2 1/2" Duals? Add a crossover over pipe, an "X" pipe, not an "H" pipe.

https://www.summitracing.com/parts/wlk-17749

I have used them before with great success, no drone. Lifetime warranty, but I never had to utilize that feature.

Magnaflow sucks. :devilish:
Click to expand...
Decided to try a pair of these Dynomax after listening to so many exhaust videos on youtube that my head is spinning. We'll see how they sound and how long they last.
 
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