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Flowmaster 40 Series Mufflers

4.81 out of 5 stars 347 Customer Reviews

Looking for the most aggressive sound in the Flowmaster muffler line? Then take a look at their 40 Series mufflers. Designed for use on street and strip vehicles, they take the sound waves produced in the exhaust, and cancel them against angled baffles built into the muffler case. This improves both horsepower and fuel economy. Best of all, they allow you to hear that cool Flowmaster tone inside of the vehicle, as well as outside. So, if you want more power and less noise, then you've got to get Flowmaster 40 Series mufflers.

Results 1 - 12 of 12

Muffler, American Thunder 40 Series, 2 1/2 in. Inlet/2 1/2 in. Outlet, Steel, Black, Each

Part Number: FLO-42541

4.73 out of 5 stars ( 82 )

Estimated Ship Date: Today

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Muffler, Flowmaster 40 Series, 3 in. Offset Inlet/3 in. Center Outlet, Steel, Black, Each

Part Number: FLO-43041

4.83 out of 5 stars ( 47 )

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Muffler, 40 Series, 2 1/2 in. Offset Inlet, 2 1/2 in. Offset Outlet, Chambered, Steel, Black, Each

Part Number: FLO-42543

4.9 out of 5 stars ( 41 )

Estimated Ship Date: Today

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Muffler, American Thunder 40 Series, 2 1/4 in. Inlet/2 1/4 in. Outlet, Steel, Black, Each

Part Number: FLO-42441

4.87 out of 5 stars ( 31 )

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Muffler, 40 Series, 2.5 in. Inlet/Outlet, Center Inlet, Offset Outlet, Aluminized Steel, Black, Each

Part Number: FLO-42542

5.0 out of 5 stars ( 12 )

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Muffler, American Thunder 40 Series, 3 in. Inlet/3 in. Outlet, Steel, Black, Each

Part Number: FLO-43043

5.0 out of 5 stars ( 10 )

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Muffler, American Thunder 40 Series, 2 1/4 in. Inlet/2 1/4 in. Outlet, Aluminized Steel, Black, Each

Part Number: FLO-42443

4.91 out of 5 stars ( 11 )

Estimated Ship Date: Today

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Muffler, 40 Series, Oval, Dual 2.5 in. Inlet/Dual 2.5 in. Outlet, Steel, Black, 19.0 in. Overall Length, Each

Part Number: FLO-425404

4.86 out of 5 stars ( 14 )

Estimated Ship Date: Today

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Muffler, American Thunder 40 Series, 3 in. Inlet/Dual 2 1/2 in. Outlet, Steel, Black, Each

Part Number: FLO-430402

4.75 out of 5 stars ( 20 )

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Muffler

Part Number: FLO-42442

4.5 out of 5 stars ( 10 )

Estimated Ship Date: Today

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Muffler, American Thunder 40 Series, 2 1/2 in. Dual Inlet/3 in. Center Outlet, Steel, Black, Each

Part Number: FLO-425403

5.0 out of 5 stars ( 6 )

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Exhaust, American Thunder, Stainless Steel, Black, Dodge, Ram, 5.7L Hemi, Each

Part Number: FLO-817568

4.76 out of 5 stars ( 63 )

Estimated Ship Date: May 8, 2025 if ordered today

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Estimated Ship Date: May 8, 2025 if ordered today

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