If you’re looking to upgrade your ride with an aggressive exhaust note that announces your presence, the Flowmaster 40 Series Single In Dual Out muffler needs to be on your radar. This iconic muffler has been setting the standard for power, sound and value for over 30 years with its traditional Flowmaster American Thunder sound. In this blog, we’ll take an in-depth look at everything you need to know about the 40 Series before you make your purchase.
Dimensions and Specifications – What Will Fit Your Ride
The Flowmaster 40 Series Single In Dual Out measures 21″ long X 12″ wide X 4.5″ tall, with 3″ inlet and outlet diameters. This compact yet powerful muffler features fully mig welded, 16 gauge aluminized steel construction with no packing material inside. It’s suitable for use on V6, V8 and turbocharged import engines up to 5.7L with stock or modified exhaust systems. The 40 Series is considered a fairly universal fit, but it’s always wise to double check clearance for your specific make and model before ordering.
The Signature Flowmaster Sound
One of the biggest draws of the 40 Series is the aggressive tone that turns heads as you roar past. The interior Delta Flow technology creates the trademark Flowmaster American Thunder sound – a deep, throaty rumble at idle that intensifies to a gnarly roar when you step on the gas. It’s louder and more resonant than stock mufflers, without being obnoxious. The sound has been described as a “muscle car” tone that’s perfect for vintage classics or modern performance vehicles.
Durable, High Quality Construction
The 40 Series casing is constructed from heavy 16 gauge aluminized steel that withstands exposure to high temperatures. This material provides maximum durability to prevent cracking, warping or rust out. The fully mig welded case seam gives a precise, clean weld for strength. Inside, there is no dense packed batting material to wear out or degrade over time. This eliminates issues with power loss, blowout and need for repacking down the road. Just clean craftsmanship and quality materials inside and out.
Configuring the Dual Outlet
The 40 Series Single In Dual Out directs exhaust through two outlets on either side of the muffler. This divided exhaust path helps reduce backpressure for increased power and performance. The dual 3″ outlets provide a symmetrical, balanced look when installed. Most choose to run both outlets out the back, but you also have the option to route them split rear and side. Creased, slashed side cut tips enhance the aggressive look when both exit the rear.
Is the 40 Series Right for You?
If you’re driving an older muscle car, hot rod or even a modern performance vehicle, and want to upgrade to that classic Flowmaster sound, the 40 Series Single In Dual Out is an excellent choice. It’s proven popular on Mustangs, Camaros, Chargers, Challengers, classic trucks, imports like BMW and Nissan models, and more. It provides an impactful roar under acceleration combined with mellow cruising. Just be sure to verify fit for your exact year, make and model. Also keep in mind it may be too loud for OEM systems.
Reasonable Cost for the Quality
The Flowmaster 40 Series Single In Dual Out carries a moderate price tag of around $170-$220 for the muffler alone. This offers a great value for a premium muffler built to last from a leading brand in exhaust systems. The cost is on par with similar products from competitors like Magnaflow, Borla and others. When professionally installed with a full exhaust system, expect to pay $500 and up for parts and labor.
Where to Buy for the Best Price
The Flowmaster 40 Series is sold through many retailers online including Summit Racing, Jegs, American Muscle, CJ Pony Parts, and Amazon. Shopping online provides more price comparison options to find the best deal. Many retailers also offer discounts, especially when bundled with other exhaust components. Be sure to use a trustworthy seller with positive reviews. Flowmaster’s website includes a dealer locator to find installers and shops local to you if buying in-store.
Professional Installation Recommended
While ambitious do-it-yourselfers may attempt installation in their own garage, having a professional shop complete the job is highly recommended. Improperly installed mufflers can lead to leaks, poor fitment, rattling, and other issues. Pro installers have the necessary lift equipment, tools and expertise to properly mount the muffler for a leak-free seal and secure fit every time. Most shops warranty their workmanship as well. Consider installation costs as part of your total investment.
Legalities of Aftermarket Exhaust
When upgrading your exhaust with products like the Flowmaster 40 Series, be aware of laws regarding sound levels and emissions. Most states and municipalities restrict noise over a certain decibel level. Added exhaust may also impact emissions, depending on your vehicle’s engine. Bring your ride to a muffler shop for debugging to ensure it still meets legal requirements for street use after installing new mufflers. Track-only vehicles allow louder, more open exhausts.
Ongoing Care and Maintenance
The 40 Series Single In Dual Out is built to last, yet still requires basic periodic care and maintenance. Avoid impact damage from debris, speed bumps and potholes that can dent or crack the case. Routinely check for leaks at the clamps and welds. Use a quality sealant to re-seal any new leaks. Clean inside the pipes with a specially formulated exhaust cleaner to prevent buildup and corrosion over time. And remember to re-tighten the clamps after initial installation and as needed.
Rave Reviews From Satisfied Drivers
Flowmaster mufflers are consistently top rated, with the 40 Series Single In Dual Out garnering glowing reviews across retailers. Owners praise the quality construction, easy bolt-on installation, great fitment, and aggressive engine tone. Many describe it as the perfect balance – not too tame but not obnoxiously loud either. Drivers report gains in acceleration, power and torque after installing the 40 Series. Any issues are rare, but include descriptions of rattling from improperly tightened clamps.
FAQs – Frequently Asked Questions
Here are answers to some of the most common questions about the Flowmaster 40 Series Single In Dual Out:
Does it come with installation clamps and hardware?
No, you’ll need to purchase clamps separately to secure the muffler. Count on two clamps. Order specifically for your diameter and type of piping.
What color is the muffler casing?
The aluminized steel construction has a shiny, chrome-like silver appearance when new. Some versions feature a black painted exterior.
Will I fail emissions testing after installation?
It shouldn’t affect emissions, but you may want to have it debugged just to be safe. Track use only permits open, louder exhausts.
Is this a bolt-on replacement for my stock muffler?
The 40 Series is designed as a direct replacement for original mufflers. Just match the inlet/outlet size and placement. Minor adjustment of the piping may be needed.
Can I run just one outlet, not both?
Yes, you can cap or bypass one of the outlets if only running a single exhaust side. Performance will be slightly reduced.
Performance Gains Across the Board
One of the best aspects of the Flowmaster 40 Series is the noticeable bump in power, acceleration and torque you’ll experience after installation. By reducing backpressure, it allows your engine to breathe better and put more power to the pavement. The sound translates to actual performance gains. Expect a 1-3mpg drop in fuel economy from the less restricted exhaust. For maximum results, pair it with a cat-back or full exhaust system. The dual outlet design further optimizes the improvements.
Additional Accessories and Components
Along with high quality clamps sized for your vehicle, there are a few other components recommended to go with your Flowmaster 40 Series purchase:
- Exhaust hangers – replace any rusted or damaged hangers when installing your new muffler.
- Exhaust piping – upgrade to larger diameter or performance pipes.
- Exhaust tip – add a slash cut, angle cut or polished tip for custom style.
- Tuning – adjust fuel mapping if installing with Headers to avoid running lean.
- Gaskets – high-temp gaskets at junction points prevent leaks. Fel-Pro and Mr. Gasket brands recommended.
Affordable Shipping with Quick Delivery
Ordering online provides affordable shipping right to your door so you can handle installation yourself or deliver to your mechanic’s shop. Expect to pay around $10-20 for standard ground shipping. Expedited air delivery is available for an extra fee to get it faster. Large retailers have warehouses nationwide, allowing for quick 1-5 day delivery times in most cases.
Undeniable Aesthetic Improvement
Beyond the auditory enhancements, installing a 40 Series muffler also visually improves your vehicle’s rear end styling. The twin chrome exhaust tips provide symmetrical balance, with options like slash cuts adding eye-catching attitude. The polished casings and dual outlets really complete the look of a performance ride. If you want to upgrade the mean growl AND the mean mug of your car or truck, this muffler nails both.
Who Gets the Most Benefit?
Some vehicles will benefit more from the 40 Series Single In Dual Out than others. V8s really come alive with the more open, rumbling tone. Higher performance cars like Mustangs, Chargers, Corvettes and Challengers experience some of the biggest gains in power and acceleration. Older muscle cars get that classic rumble back. And import fans benefit from the cost-effective value for these mufflers. If you drive aggressively and want more throttle response, this muffler delivers the sound and performance to match.
In summary, if you’re searching for a muffler that kicks out an old-school muscle car sound with increased power, torque and responsiveness – while looking great from behind – the iconic Flowmaster 40 Series Single In Dual Out is a leading choice that delivers on all fronts. This moderately priced workhorse has been proven over decades and hundreds of thousands of satisfied customers as one of the best bang-for-your-buck upgrades you can bolt on. Just be sure to verify fitment for your specific vehicle before purchase. Pair it with a cat-back exhaust system and performance upgrades to maximize benefits. With proper installation and routine care, the 40 Series will be announcing your presence for years to come.
