Flowmaster 40 Series Chambered Muffler

40 Series - 2.25 Offset In / 2.25 Center Out - Aggressive Sound

Inlet Position

Material

Outlet Position

Part # 42441

4 Reviews

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MSRP $112.95

$89.96

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Emissions

This part is legal for sale or use on Emissions Controlled Vehicles, Uncontrolled (Non-Emissions Controlled) Vehicles, and Racing Use Only Vehicles because it does not affect vehicle emissions and is not covered by emissions regulations.

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The Original 40 series muffler delivers an aggressive exterior and interior tone. If you're looking for that original Flowmaster sound this is the muffler is for you. Constructed of 16 gauge aluminized steel and fully MIG welded for maximum durability.

Features:

Excellent Street/Strip and Off Road application
Noticeable interior resonance
Aggressive Sound Exterior Exhaust Tone
Durable fully welded 16 gauge aluminized steel

About Flowmaster

Shop the complete line of Flowmaster products for exhaust systems, mufflers, and more that deliver the iconic Flowmaster sound. Available at Holley.com!

Automotive Item Grade	High Performance
Body Height	4.00 IN
Body Length	13.00 IN
Body Material	Aluminized Steel
Body Width	9.50 IN
Brand	Flowmaster
Category	Exhaust
Clamps Included	No
Color	Black
Emission Code	5
Exhaust Tip Quantity	0
Finish	Paint
Fitment	Universal
Grade Type	Performance
Hanger Included	No
Heat Shield Attached	No
Inlet Connection Type	Pipe Connection
Inlet Diameter	2.25 IN
Inlet Inside Diameter	2.25 IN
Inlet Location	Offset
Inlet Outside Diameter	2.38 IN
Inlet Position	Offset
Inlet Quantity	1
Inlet Type	Clamp-On
	Weld-On
Material	Aluminized Steel
Muffler Series	Original 40 Series
Muffler Type	Chambered
Outlet Diameter	2.25 IN
Outlet Inside Diameter	2.25 IN
Outlet Location	Center
Outlet Outside Diameter	2.38 IN
Outlet Position	Center
Outlet Quantity	1
Outlet Type	Single
Overall Length	19.40 IN
Part Type	Exhaust Muffler
Product Type	Street Mufflers
Reversible	No
Shape	Oval
Sound Level	Aggressive Sound
Sub Category	Mufflers
Tunable	No
Type of Muffler	Chambered
Universal Or Specific Fit	Universal
Vehicle Type	Classic Muscle Car
	Late Model Muscle Car
	Street Rod
	Street/Strip
	Truck/SUV
UPC	700042010295
California Proposition 65 Required	No
Part Number	42441

Instructions - fm_warranty_general.pdf

Instructions - street_applications.pdf

Universal Muffler - Some adaptation may be required.

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40 Series Muffler

By Maynard R on March 29, 2019

I recently purchased the Flowmaster 17428 Cat Back System for my 2001 Chevrolet Silverado Pick up. Reading and understanding the instructions this thing went in in less than 2 hours and I did it in my Garage, with Truck on Jack Stands. Start your truck and let it get to running temperature which will help with Bolt and Nut Removal. Spray all the affected Nuts and Bolts with a Penetrating oil, WD, kROIL, ETC. I found this to help the removal of your existing system is to cut the Tail Pipe assembly right behind the existing Muffler, and remove. Loosen and remove the Nuts that attach your existing system to the Cats. Remove that section of Pipe and Muffler. Install the 3" Diameter section of Pipe, and stick into the existing hanger. Bolt it up but do not Tighten. Install your Muffler per the diagram that comes with your system. And install the 2-1/2" Exit Pipes and tighten Clamps but do not Finish! Install the Tips and use a gauge like a piece of wood to angle them the way you like.Then go back and tighten everything from the Tail tips back to the 3" Main Pipe that attaches to the Cats. Start the Truck and let it run. It will Purr Like a Kitten on steroids! I am very happy with this system and would recommend this system if you want a Truck to sound like a Truck! Next will be the Cats and then Headers and then a New motor will be installed. I hope this helps and am very happy with the sound. There is hardly any Drone and you can carry on a conversation while driving at any speed. Drone zero's at 80 MPH!Hope it makes you as happy as myself.

Custom job

By JAMES M on October 3, 2019

I recently had a custom install of two 42441's on my '05 Silverado 4.3L single cab manual 5-speed. Had my exhaust tech cut the single pipe and factory muffler off just behind the converters and ran two new pipes, connected two 42441's and two 2.5 inch tips turned down just at the outlet, in front of the axle. When the tech pulled my truck out of the bay and to the front of the shop, I didn't recognize the sound of my truck. It rumbled. Not quite like a V-8, but it rumbled. I took a 400 mile road trip just after the install and noticed a 1.5 to 2 mpg improvement and a bit better low end torque. The sound was great during acceleration but had a harsh resonance in the cab between 1500 and 2000 rpm, which is between 60 and 70 mph (highway speeds). I may have to extend the tail pipes out the back or at least to the side just behind the rear tires to curtail that deep vibration. I am pleased with the overall performance though, plus my guy did a great job on the install and gave me a great deal at Midstate Tire in Carthage, MS. Tell him Jeff Mills sent you.

Absolutely Love The Sound!!

By Brock B on November 19, 2019

I put these mufflers on my 1994 Ford f-250 with a 460 motor. True dual 2.5inch pipe setup and these mufflers. The sound is deep and pretty loud. pretty choppy and sounds Great. I absolutely love the sound.

Muffler

By colton m on June 7, 2021 | Verified Owner

Sounds good on my car. Only downside was inlet and out let's were too big for my car.

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*Free Shipping and Handling only offered to the contiguous US on orders over $149, excludes clearance parts and oversized packages.

Some parts are not legal for use in California or other states with similar regulations.

Flowmaster 40 Series Chambered Muffler

Inlet Position

Material

Outlet Position

Flowmaster 40 Series Chambered Muffler

Emissions

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